diff --git a/1899/B.java b/1899/B.java
new file mode 100644
index 0000000..60aa93f
--- /dev/null
+++ b/1899/B.java
@@ -0,0 +1,187 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Random;
+import java.util.StringTokenizer;
+
+class Solution {
+    void solve() {
+        var n = fs.nextInt();
+        var a = fs.readArray(n);
+
+        var prefix = new long[n + 2];
+        for (int i = 0; i < n; ++i) {
+            prefix[i + 1] = prefix[i] + a[i];
+        }
+
+        long max = 0;
+        for (int k = 1; n / k > 1; ++k) {
+            if (n % k != 0) {
+                continue;
+            }
+
+            long _min = Long.MAX_VALUE, _max = Long.MIN_VALUE;
+            for (int i = 0, count = n / k; i < count; ++i) {
+                long truck = prefix[(i + 1) * k] - prefix[i * k];
+
+                if (truck < _min) {
+                    _min = truck;
+                }
+                if (truck > _max) {
+                    _max = truck;
+                }
+            }
+
+            if (_max - _min > max) {
+                max = _max - _min;
+            }
+        }
+
+        answer(max);
+    }
+
+    // region runner
+    private static final boolean SINGLE = false;
+    void run() {
+        if (SINGLE) {
+            solve();
+        } else {
+            int N = fs.nextInt();
+            for (int i = 0; i < N; ++i) {
+                solve();
+            }
+        }
+
+        out.close();
+    }
+
+    public static void main(String[] args) {
+        new Solution().run();
+    }
+    // endregion runner
+
+    // region math
+    static final Random random = new Random();
+    static final int mod = 1_000_000_007;
+
+    static long add(long a, long b) {
+        return (a + b) % mod;
+    }
+
+    static long sub(long a, long b) {
+        return ((a - b) % mod + mod) % mod;
+    }
+
+    static long mul(long a, long b) {
+        return (a * b) % mod;
+    }
+
+    static long exp(long base, long exp) {
+        if (exp == 0)
+            return 1;
+        long half = exp(base, exp / 2);
+        if (exp % 2 == 0)
+            return mul(half, half);
+        return mul(half, mul(half, base));
+    }
+
+    static long[] factorials = new long[2_000_001];
+    static long[] invFactorials = new long[2_000_001];
+
+    static void precompFacts() {
+        factorials[0] = invFactorials[0] = 1;
+        for (int i = 1; i < factorials.length; i++)
+            factorials[i] = mul(factorials[i - 1], i);
+        invFactorials[factorials.length - 1] = exp(factorials[factorials.length - 1], mod - 2);
+        for (int i = invFactorials.length - 2; i >= 0; i--)
+            invFactorials[i] = mul(invFactorials[i + 1], i + 1);
+    }
+
+    static long nCk(int n, int k) {
+        return mul(factorials[n], mul(invFactorials[k], invFactorials[n - k]));
+    }
+    // endregion math
+
+    // region sorts
+    static void ruffleSort(int[] a) {
+        int n = a.length;// shuffle, then sort
+        for (int i = 0; i < n; i++) {
+            int oi = random.nextInt(n), temp = a[oi];
+            a[oi] = a[i];
+            a[i] = temp;
+        }
+        Arrays.sort(a);
+    }
+
+    static void sort(int[] a) {
+        ArrayList<Integer> l = new ArrayList<>();
+        for (int i : a)
+            l.add(i);
+        Collections.sort(l);
+        for (int i = 0; i < a.length; i++)
+            a[i] = l.get(i);
+    }
+    // endregion sorts
+
+    // region output
+    private PrintWriter out = new PrintWriter(System.out);
+
+    private void yes() {
+        out.println("YES");
+    }
+
+    private void no() {
+        out.println("NO");
+    }
+
+    private void yesno(boolean ans) {
+        out.println(ans ? "YES" : "NO");
+    }
+
+    private void answer(boolean ans) {
+        yesno(ans);
+    }
+
+    private <T> void answer(T ans) {
+        out.println(ans);
+    }
+    // endregion output
+
+    // region input
+    static class FastScanner {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer("");
+
+        String next() {
+            while (!st.hasMoreTokens())
+                try {
+                    st = new StringTokenizer(br.readLine());
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            return st.nextToken();
+        }
+
+        int nextInt() {
+            return Integer.parseInt(next());
+        }
+
+        int[] readArray(int n) {
+            int[] a = new int[n];
+            for (int i = 0; i < n; i++)
+                a[i] = nextInt();
+            return a;
+        }
+
+        long nextLong() {
+            return Long.parseLong(next());
+        }
+    }
+    private FastScanner fs = new FastScanner();
+    // endregion input
+
+}
diff --git a/1899/E.java b/1899/E.java
new file mode 100644
index 0000000..ed10944
--- /dev/null
+++ b/1899/E.java
@@ -0,0 +1,175 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Random;
+import java.util.StringTokenizer;
+
+class Solution {
+    void solve() {
+        var n = fs.nextInt();
+        var a = fs.readArray(n);
+
+        // find the minimum
+        int min_idx = 0;
+        for (int i = 1; i < a.length; ++i) {
+            if (a[i] < a[min_idx]) {
+                min_idx = i;
+            }
+        }
+
+        // check the rest of the array
+        for (int i = min_idx + 1; i < a.length; ++i) {
+            if (a[i - 1] > a[i]) {
+                answer(-1);
+                return;
+            }
+        }
+
+        answer(min_idx);
+    }
+
+    // region runner
+    private static final boolean SINGLE = false;
+    void run() {
+        if (SINGLE) {
+            solve();
+        } else {
+            int N = fs.nextInt();
+            for (int i = 0; i < N; ++i) {
+                solve();
+            }
+        }
+
+        out.close();
+    }
+
+    public static void main(String[] args) {
+        new Solution().run();
+    }
+    // endregion runner
+
+    // region math
+    static final Random random = new Random();
+    static final int mod = 1_000_000_007;
+
+    static long add(long a, long b) {
+        return (a + b) % mod;
+    }
+
+    static long sub(long a, long b) {
+        return ((a - b) % mod + mod) % mod;
+    }
+
+    static long mul(long a, long b) {
+        return (a * b) % mod;
+    }
+
+    static long exp(long base, long exp) {
+        if (exp == 0)
+            return 1;
+        long half = exp(base, exp / 2);
+        if (exp % 2 == 0)
+            return mul(half, half);
+        return mul(half, mul(half, base));
+    }
+
+    static long[] factorials = new long[2_000_001];
+    static long[] invFactorials = new long[2_000_001];
+
+    static void precompFacts() {
+        factorials[0] = invFactorials[0] = 1;
+        for (int i = 1; i < factorials.length; i++)
+            factorials[i] = mul(factorials[i - 1], i);
+        invFactorials[factorials.length - 1] = exp(factorials[factorials.length - 1], mod - 2);
+        for (int i = invFactorials.length - 2; i >= 0; i--)
+            invFactorials[i] = mul(invFactorials[i + 1], i + 1);
+    }
+
+    static long nCk(int n, int k) {
+        return mul(factorials[n], mul(invFactorials[k], invFactorials[n - k]));
+    }
+    // endregion math
+
+    // region sorts
+    static void ruffleSort(int[] a) {
+        int n = a.length;// shuffle, then sort
+        for (int i = 0; i < n; i++) {
+            int oi = random.nextInt(n), temp = a[oi];
+            a[oi] = a[i];
+            a[i] = temp;
+        }
+        Arrays.sort(a);
+    }
+
+    static void sort(int[] a) {
+        ArrayList<Integer> l = new ArrayList<>();
+        for (int i : a)
+            l.add(i);
+        Collections.sort(l);
+        for (int i = 0; i < a.length; i++)
+            a[i] = l.get(i);
+    }
+    // endregion sorts
+
+    // region output
+    private PrintWriter out = new PrintWriter(System.out);
+
+    private void yes() {
+        out.println("YES");
+    }
+
+    private void no() {
+        out.println("NO");
+    }
+
+    private void yesno(boolean ans) {
+        out.println(ans ? "YES" : "NO");
+    }
+
+    private void answer(boolean ans) {
+        yesno(ans);
+    }
+
+    private <T> void answer(T ans) {
+        out.println(ans);
+    }
+    // endregion output
+
+    // region input
+    static class FastScanner {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer("");
+
+        String next() {
+            while (!st.hasMoreTokens())
+                try {
+                    st = new StringTokenizer(br.readLine());
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            return st.nextToken();
+        }
+
+        int nextInt() {
+            return Integer.parseInt(next());
+        }
+
+        int[] readArray(int n) {
+            int[] a = new int[n];
+            for (int i = 0; i < n; i++)
+                a[i] = nextInt();
+            return a;
+        }
+
+        long nextLong() {
+            return Long.parseLong(next());
+        }
+    }
+    private FastScanner fs = new FastScanner();
+    // endregion input
+
+}
diff --git a/1899/a.cpp b/1899/a.cpp
new file mode 100644
index 0000000..61b0a7f
--- /dev/null
+++ b/1899/a.cpp
@@ -0,0 +1,318 @@
+#include <algorithm>
+#include <array>
+#include <bit>
+#include <bitset>
+#include <cassert>
+#include <cctype>
+#include <chrono>
+#include <cmath>
+#include <cstdint>
+#include <functional>
+#include <iomanip>
+#include <iostream>
+#include <map>
+#include <numeric>
+#include <optional>
+#include <queue>
+#include <random>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#pragma region helpers
+
+#pragma region aliases
+#define LOOP(var, n) for (auto var = 0; var < n; ++var)
+
+template <typename T>
+using V = std::vector<T>;
+
+template <typename K, typename V>
+using M = std::map<K, V>;
+
+template <typename T>
+using S = std::set<T>;
+
+template <typename T>
+using Q = std::deque<T>;
+
+using i8 = std::int8_t;
+using u8 = std::uint8_t;
+using i16 = std::int16_t;
+using u16 = std::uint16_t;
+using i32 = std::int32_t;
+using u32 = std::uint32_t;
+using i64 = std::int64_t;
+using u64 = std::uint64_t;
+#pragma endregion /* aliases */
+
+#pragma region data structures
+template <typename T>
+struct max_heap {
+  using container = std::vector<T>;
+
+  typename container::size_type size() const { return h.size(); }
+
+  void push(T item) {
+    h.push_back(item);
+    std::push_heap(h.begin(), h.end());
+  }
+
+  T pop() {
+    std::pop_heap(h.begin(), h.end());
+    T item = std::move(h.back());
+    h.pop_back();
+    return item;
+  }
+
+ private:
+  container h;
+};
+
+template <typename T>
+struct min_heap {
+  using container = std::vector<T>;
+
+  typename container::size_type size() const { return h.size(); }
+
+  void push(T item) {
+    h.push_back(item);
+    std::push_heap(h.begin(), h.end(), std::greater<>{});
+  }
+
+  T pop() {
+    std::pop_heap(h.begin(), h.end(), std::greater<>{});
+    T item = std::move(h.back());
+    h.pop_back();
+    return item;
+  }
+
+ private:
+  container h;
+};
+#pragma endregion /* data structures */
+
+#pragma region debug
+void dbg_out() { std::cerr << std::endl; }
+template <typename Head, typename... Tail>
+void dbg_out(Head H, Tail... T) {
+  std::cerr << ' ' << H;
+  dbg_out(T...);
+}
+#ifdef LOCAL
+#define dbg(...)                                                           \
+  std::cerr << '[' << __FILE__ << ':' << __LINE__ << "] (" << #__VA_ARGS__ \
+            << "):",                                                       \
+      dbg_out(__VA_ARGS__)
+#else
+#define dbg(...)
+#endif
+#pragma endregion debug
+
+#pragma region functional
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0200r0.html
+template <class Fun>
+class y_combinator_result {
+  Fun fun_;
+
+ public:
+  template <class T>
+  explicit y_combinator_result(T &&fun) : fun_(std::forward<T>(fun)) {}
+  template <class... Args>
+  decltype(auto) operator()(Args &&...args) {
+    return fun_(std::ref(*this), std::forward<Args>(args)...);
+  }
+};
+template <class Fun>
+decltype(auto) y_combinator(Fun &&fun) {
+  return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
+}
+#pragma endregion /* functional */
+
+#pragma region input
+template <typename Container>
+void collect(Container &c, std::size_t size) {
+  auto it = std::inserter(c, c.begin());
+
+  for (auto i = 0u; i < size; ++i) {
+    typename Container::value_type x;
+    std::cin >> x;
+    it = std::move(x);
+  }
+}
+
+template <typename Container>
+Container collect(std::size_t size) {
+  Container c{};
+  collect(c, size);
+  return c;
+}
+#pragma endregion /* input */
+
+#pragma region math
+long pow(long base, long exp) {
+  if (exp == 0) return 1;
+  long half = pow(base, exp / 2);
+  if (exp % 2 == 0) return half * half;
+  return half * half * base;
+}
+
+template <typename T>
+T isqrt(T x) {
+  assert(x >= 0);
+
+  auto max_shift = 8 * sizeof(T) - 1;
+  auto shift = (max_shift - std::countl_zero(x)) & ~1;
+  auto bit = 1 << shift;
+
+  T result = 0;
+  while (bit != 0) {
+    if (x >= (result + bit)) {
+      x -= result + bit;
+      result = (result >> 1) + bit;
+    } else {
+      result = (result >> 1);
+    }
+    bit = bit >> 2;
+  }
+
+  return result;
+}
+
+template <std::int64_t MODULO = 1000000007>
+struct Z {
+  Z(std::int64_t x = 0) : x(x % MODULO) {}
+
+  Z pow(std::uint32_t exp) const {
+    auto ans = 1;
+    auto base = x;
+
+    for (; exp > 0; exp >>= 1) {
+      if (exp % 2 == 1) {
+        ans *= base;
+      }
+
+      base *= base;
+    }
+
+    return ans;
+  }
+
+  Z inv() const {
+    assert(x != 0);
+    return pow(MODULO - 2);
+  }
+
+  Z operator-() const { return {-x}; }
+  Z operator+=(const Z &rhs) { x = (x + rhs.x) % MODULO; }
+  Z operator-=(const Z &rhs) { x = (x - rhs.x) % MODULO; }
+  Z operator*=(const Z &rhs) { x = (x * rhs.x) % MODULO; }
+  Z operator/=(const Z &rhs) { x = (x * rhs.inv().x) % MODULO; }
+
+  friend Z operator+(Z lhs, const Z &rhs) { return lhs += rhs; }
+  friend Z operator-(Z lhs, const Z &rhs) { return lhs -= rhs; }
+  friend Z operator*(Z lhs, const Z &rhs) { return lhs *= rhs; }
+  friend Z operator/(Z lhs, const Z &rhs) { return lhs /= rhs; }
+
+  friend std::istream &operator>>(std::istream &is, Z &z) {
+    is >> z.x;
+    z.x %= MODULO;
+    return is;
+  }
+
+  friend std::ostream &operator<<(std::ostream &os, const Z &z) {
+    return os << z.x;
+  }
+
+ private:
+  std::int64_t x;
+};
+#pragma endregion /* math */
+
+#pragma region output
+template <typename T, typename U>
+std::ostream &operator<<(std::ostream &os, std::pair<T, U> const &p) {
+  return os << p.first << " " << p.second;
+}
+
+template <typename C, typename T = typename std::enable_if<
+                          !std::is_same<C, std::string>::value,
+                          typename C::value_type>::type>
+std::ostream &operator<<(std::ostream &os, const C &v) {
+  std::string sep;
+  for (const T &x : v) {
+    os << sep << x, sep = " ";
+  }
+
+  return os;
+}
+
+template <typename T>
+inline void answer(const T &ans) {
+  std::cout << ans << "\n";
+}
+
+inline void yes() { std::cout << "YES\n"; }
+inline void no() { std::cout << "NO\n"; }
+inline void yesno(bool ans) { std::cout << (ans ? "YES" : "NO") << "\n"; }
+#pragma endregion /* output */
+
+#pragma region rng
+std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
+#pragma endregion /* rng */
+
+#pragma endregion /* helpers */
+
+// for ‹N› test cases, uncomment for single test case
+// #define SINGLE
+
+namespace solution {
+
+using namespace std;
+
+void solve() {
+  int x;
+  cin >> x;
+
+  if (x % 3 != 0) {
+    answer("First");
+  } else {
+    answer("Second");
+  }
+}
+
+void tests() {
+  // TODO
+}
+
+}  // namespace solution
+
+using namespace solution;
+
+#ifdef TEST
+
+int main(void) {
+  tests();
+  return 0;
+}
+
+#else
+
+int main(void) {
+  int N = 1;
+
+#ifndef SINGLE
+
+  std::cin >> N;
+
+#endif
+
+  while (N-- > 0) {
+    solve();
+  }
+
+  return 0;
+}
+
+#endif
diff --git a/1899/c.cpp b/1899/c.cpp
new file mode 100644
index 0000000..cb97a24
--- /dev/null
+++ b/1899/c.cpp
@@ -0,0 +1,329 @@
+#include <algorithm>
+#include <array>
+#include <bit>
+#include <bitset>
+#include <cassert>
+#include <cctype>
+#include <chrono>
+#include <cmath>
+#include <cstdint>
+#include <functional>
+#include <iomanip>
+#include <iostream>
+#include <map>
+#include <numeric>
+#include <optional>
+#include <queue>
+#include <random>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#pragma region helpers
+
+#pragma region aliases
+#define LOOP(var, n) for (auto var = 0; var < n; ++var)
+
+template <typename T>
+using V = std::vector<T>;
+
+template <typename K, typename V>
+using M = std::map<K, V>;
+
+template <typename T>
+using S = std::set<T>;
+
+template <typename T>
+using Q = std::deque<T>;
+
+using i8 = std::int8_t;
+using u8 = std::uint8_t;
+using i16 = std::int16_t;
+using u16 = std::uint16_t;
+using i32 = std::int32_t;
+using u32 = std::uint32_t;
+using i64 = std::int64_t;
+using u64 = std::uint64_t;
+#pragma endregion /* aliases */
+
+#pragma region data structures
+template <typename T>
+struct max_heap {
+  using container = std::vector<T>;
+
+  typename container::size_type size() const { return h.size(); }
+
+  void push(T item) {
+    h.push_back(item);
+    std::push_heap(h.begin(), h.end());
+  }
+
+  T pop() {
+    std::pop_heap(h.begin(), h.end());
+    T item = std::move(h.back());
+    h.pop_back();
+    return item;
+  }
+
+ private:
+  container h;
+};
+
+template <typename T>
+struct min_heap {
+  using container = std::vector<T>;
+
+  typename container::size_type size() const { return h.size(); }
+
+  void push(T item) {
+    h.push_back(item);
+    std::push_heap(h.begin(), h.end(), std::greater<>{});
+  }
+
+  T pop() {
+    std::pop_heap(h.begin(), h.end(), std::greater<>{});
+    T item = std::move(h.back());
+    h.pop_back();
+    return item;
+  }
+
+ private:
+  container h;
+};
+#pragma endregion /* data structures */
+
+#pragma region debug
+void dbg_out() { std::cerr << std::endl; }
+template <typename Head, typename... Tail>
+void dbg_out(Head H, Tail... T) {
+  std::cerr << ' ' << H;
+  dbg_out(T...);
+}
+#ifdef LOCAL
+#define dbg(...)                                                           \
+  std::cerr << '[' << __FILE__ << ':' << __LINE__ << "] (" << #__VA_ARGS__ \
+            << "):",                                                       \
+      dbg_out(__VA_ARGS__)
+#else
+#define dbg(...)
+#endif
+#pragma endregion debug
+
+#pragma region functional
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0200r0.html
+template <class Fun>
+class y_combinator_result {
+  Fun fun_;
+
+ public:
+  template <class T>
+  explicit y_combinator_result(T &&fun) : fun_(std::forward<T>(fun)) {}
+  template <class... Args>
+  decltype(auto) operator()(Args &&...args) {
+    return fun_(std::ref(*this), std::forward<Args>(args)...);
+  }
+};
+template <class Fun>
+decltype(auto) y_combinator(Fun &&fun) {
+  return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
+}
+#pragma endregion /* functional */
+
+#pragma region input
+template <typename Container>
+void collect(Container &c, std::size_t size) {
+  auto it = std::inserter(c, c.begin());
+
+  for (auto i = 0u; i < size; ++i) {
+    typename Container::value_type x;
+    std::cin >> x;
+    it = std::move(x);
+  }
+}
+
+template <typename Container>
+Container collect(std::size_t size) {
+  Container c{};
+  collect(c, size);
+  return c;
+}
+#pragma endregion /* input */
+
+#pragma region math
+long pow(long base, long exp) {
+  if (exp == 0) return 1;
+  long half = pow(base, exp / 2);
+  if (exp % 2 == 0) return half * half;
+  return half * half * base;
+}
+
+template <typename T>
+T isqrt(T x) {
+  assert(x >= 0);
+
+  auto max_shift = 8 * sizeof(T) - 1;
+  auto shift = (max_shift - std::countl_zero(x)) & ~1;
+  auto bit = 1 << shift;
+
+  T result = 0;
+  while (bit != 0) {
+    if (x >= (result + bit)) {
+      x -= result + bit;
+      result = (result >> 1) + bit;
+    } else {
+      result = (result >> 1);
+    }
+    bit = bit >> 2;
+  }
+
+  return result;
+}
+
+template <std::int64_t MODULO = 1000000007>
+struct Z {
+  Z(std::int64_t x = 0) : x(x % MODULO) {}
+
+  Z pow(std::uint32_t exp) const {
+    auto ans = 1;
+    auto base = x;
+
+    for (; exp > 0; exp >>= 1) {
+      if (exp % 2 == 1) {
+        ans *= base;
+      }
+
+      base *= base;
+    }
+
+    return ans;
+  }
+
+  Z inv() const {
+    assert(x != 0);
+    return pow(MODULO - 2);
+  }
+
+  Z operator-() const { return {-x}; }
+  Z operator+=(const Z &rhs) { x = (x + rhs.x) % MODULO; }
+  Z operator-=(const Z &rhs) { x = (x - rhs.x) % MODULO; }
+  Z operator*=(const Z &rhs) { x = (x * rhs.x) % MODULO; }
+  Z operator/=(const Z &rhs) { x = (x * rhs.inv().x) % MODULO; }
+
+  friend Z operator+(Z lhs, const Z &rhs) { return lhs += rhs; }
+  friend Z operator-(Z lhs, const Z &rhs) { return lhs -= rhs; }
+  friend Z operator*(Z lhs, const Z &rhs) { return lhs *= rhs; }
+  friend Z operator/(Z lhs, const Z &rhs) { return lhs /= rhs; }
+
+  friend std::istream &operator>>(std::istream &is, Z &z) {
+    is >> z.x;
+    z.x %= MODULO;
+    return is;
+  }
+
+  friend std::ostream &operator<<(std::ostream &os, const Z &z) {
+    return os << z.x;
+  }
+
+ private:
+  std::int64_t x;
+};
+#pragma endregion /* math */
+
+#pragma region output
+template <typename T, typename U>
+std::ostream &operator<<(std::ostream &os, std::pair<T, U> const &p) {
+  return os << p.first << " " << p.second;
+}
+
+template <typename C, typename T = typename std::enable_if<
+                          !std::is_same<C, std::string>::value,
+                          typename C::value_type>::type>
+std::ostream &operator<<(std::ostream &os, const C &v) {
+  std::string sep;
+  for (const T &x : v) {
+    os << sep << x, sep = " ";
+  }
+
+  return os;
+}
+
+template <typename T>
+inline void answer(const T &ans) {
+  std::cout << ans << "\n";
+}
+
+inline void yes() { std::cout << "YES\n"; }
+inline void no() { std::cout << "NO\n"; }
+inline void yesno(bool ans) { std::cout << (ans ? "YES" : "NO") << "\n"; }
+#pragma endregion /* output */
+
+#pragma region rng
+std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
+#pragma endregion /* rng */
+
+#pragma endregion /* helpers */
+
+// for ‹N› test cases, uncomment for single test case
+// #define SINGLE
+
+namespace solution {
+
+using namespace std;
+
+void solve() {
+  size_t n;
+  cin >> n;
+
+  auto a = collect<V<int>>(n);
+
+  auto m = *max_element(a.begin(), a.end());
+  auto k = a[0];
+
+  for (size_t i = 1; i < n; ++i) {
+    if (abs(a[i - 1] % 2) == abs(a[i] % 2)) {
+      k = a[i];
+    } else {
+      k = max(k + a[i], a[i]);
+    }
+
+    m = max(m, k);
+  }
+
+  answer(m);
+}
+
+void tests() {
+  // TODO
+}
+
+}  // namespace solution
+
+using namespace solution;
+
+#ifdef TEST
+
+int main(void) {
+  tests();
+  return 0;
+}
+
+#else
+
+int main(void) {
+  int N = 1;
+
+#ifndef SINGLE
+
+  std::cin >> N;
+
+#endif
+
+  while (N-- > 0) {
+    solve();
+  }
+
+  return 0;
+}
+
+#endif