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

using namespace std;

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

const int NMAX = 100005;

vector <int>v[NMAX];
bool viz[NMAX];

void dfs(int x){
    viz[x] = 1;
    for(int i = 0;i<v[x].size();i++){
        int y = v[x][i];
        if(!viz[y])
            dfs(y);
    }
}

int main(){
    int n, m;
    in >> n >> m;
    for(int i=1;i<=n;i++){
        int x, y;
        in >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int nr = 0;
    for(int i=1;i<=n;i++){
        if(!viz[i]){
            dfs(i);
            nr ++;
        }
    }
    out << nr;
    return 0;
}