package main

func removeStones(stones [][]int) int {
	n := len(stones)

	makeGraph := func() ([][]int, []bool) {
		g := make([][]int, n)

		for i := range n {
			for j := i + 1; j < n; j++ {
				if stones[i][0] == stones[j][0] || stones[i][1] == stones[j][1] {
					g[i] = append(g[i], j)
					g[j] = append(g[j], i)
				}
			}
		}

		return g, make([]bool, n)
	}
	g, visited := makeGraph()

	var runDFS func(int)
	runDFS = func(u int) {
		visited[u] = true

		for _, v := range g[u] {
			if !visited[v] {
				runDFS(v)
			}
		}
	}

	components := 0

	for i := range n {
		if !visited[i] {
			runDFS(i)
			components++
		}
	}

	return n - components
}