1using System;
2using System.Collections.Generic;
3
4class UnionFind {
5    private int[] parent, rank, size;
6    public UnionFind(int n) {
7        parent = new int[n];
8        rank = new int[n];
9        size = new int[n];
10        for (int i = 0; i < n; i++) {
11            parent[i] = i;
12            size[i] = 1;
13        }
14    }
    public int Find(int a) {
        if (parent[a] != a) parent[a] = Find(parent[a]);
        return parent[a];
    }
    public void Union(int a, int b) {
        int rootA = Find(a);
        int rootB = Find(b);
        if (rootA != rootB) {
            if (rank[rootA] > rank[rootB]) {
                parent[rootB] = rootA;
                size[rootA] += size[rootB];
            } else if (rank[rootA] < rank[rootB]) {
                parent[rootA] = rootB;
                size[rootB] += size[rootA];
            } else {
                parent[rootB] = rootA;
                rank[rootA]++;
                size[rootA] += size[rootB];
            }
        }
    }
    public int ComponentSize(int a) {
        return size[Find(a)];
    }
}

public class UnreachablePairs {
    public static int CountUnreachablePairs(int n, int[][] edges) {
        UnionFind uf = new UnionFind(n);
        foreach (int[] edge in edges) {
            uf.Union(edge[0], edge[1]);
        }

        long totalPairs = (long)n * (n - 1) / 2;
        long reachablePairs = 0;
        HashSet<int> uniqueRoots = new HashSet<int>();
        for (int i = 0; i < n; i++) {
            uniqueRoots.Add(uf.Find(i));
        }

        foreach (int root in uniqueRoots) {
            int c_size = uf.ComponentSize(root);
            reachablePairs += (long)c_size * (c_size - 1) / 2;
        }

        return (int)(totalPairs - reachablePairs);
    }

    public static void Main(string[] args) {
        int n = 7;
        int[][] edges = { new int[] {0, 2}, new int[] {0, 5}, new int[] {2, 4}, new int[] {1, 6}, new int[] {5, 4} };
        Console.WriteLine(CountUnreachablePairs(n, edges));
    }
}