#include <bits/stdc++.h>

std::ifstream f("dfs.in");
std::ofstream g("dfs.out");

int T[100001], viz[1000001], n;

void dfs(int x){
    viz[x] = 1;
    for(int i = 1; i <= n; ++i)
        if(viz[i] == 0 && T[i] == x)
            dfs(i);
}

int main()
{
    int
     m, x, y, nr = 0;
    f >> n >> m;
    while(m--){
        f >> x >> y;
        T[x] = y;
        T[y] = x;
    }
    for(int i = 1; i <= n; ++i){
        if(viz[i] == 0){
            dfs(i);
            nr++;
        }
    }
    g << nr;
    return 0;
}