Number of good components

//Number of good components

import java.io.*;
import java.util.*;

class IntMatrix {
    public static int[][] input(BufferedReader br, int n, int m) throws IOException {
        int[][] mat = new int[n][];

        for(int i = 0; i < n; i++) {
            String[] s = br.readLine().trim().split(" ");
            mat[i] = new int[s.length];

            for(int j = 0; j < s.length; j++)
              mat[i][j] = Integer.parseInt(s[j]);
        }

        return mat;
    }

    public static void print(int[][] m) {
        for(var a : m) {
            for(int e : a)
              System.out.print(e + " ");
            System.out.println();
        }
    }

    public static void print(ArrayList<ArrayList<Integer>> m) {
        for(var a : m) {
            for(int e : a)
              System.out.print(e + " ");
            System.out.println();
        }
    }
}

class GFG {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(br.readLine());

        while(t-- > 0) {
            int e = Integer.parseInt(br.readLine());
            int v = Integer.parseInt(br.readLine());
            int[][] edges = IntMatrix.input(br, e, 2);
            Solution obj = new Solution();
            int res = obj.findNumberOfGoodComponent(e, v, edges);
            System.out.println(res);
        }
    }
}

class Solution {
    static int v_count;
    static int e_count;
    static boolean vis[];
    
    public static int findNumberOfGoodComponent(int e, int V, int[][] edges) {
        ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
        
        for(int i = 0; i <= V; i++) {
            adj.add(new ArrayList<>());
        }
        
        for(int[] edge : edges) {
            adj.get(edge[0]).add(edge[1]);
            adj.get(edge[1]).add(edge[0]);
        }
        
        vis = new boolean[V + 1];
        int ans = 0;
        
        for(int i = 1; i <= V; i++) {
            if(!vis[i]) {
                v_count = e_count = 0;
                dfs(adj, i);
            
                if(e_count == (v_count *(v_count - 1))) {
                    ans++;
                }
            }
        }
        
        return ans;
    }
    
    static void dfs(ArrayList<ArrayList<Integer>> adj, int st) {
        vis[st] = true;
        v_count++;
        e_count += adj.get(st).size();

        for(int nei : adj.get(st)) {
            if(!vis[nei]) {
                dfs(adj, nei);
            }
        }
    }

}