#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

int n, m, comp;
bool viz[1000000];
vector <int> a[1000000];

ifstream in("dfs.in");
ofstream out("dfs.out");

void dfs(int node){
    if(viz[node] == 1) return;
    for(auto i : a[node]){
        if(viz[i] == 0) {
            comp++;
            viz[i] = 1;
        }
    }
}

int main()
{
    int x, y;
    in >> n >> m;
    for(int i = 1; i <= m; i++){
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    for(int i = 1; i <= m; i++){
        dfs(i);
    }

    cout << comp;
    return 0;
}