#include<fstream>
#include<vector>
using namespace std;
ofstream out("dfs.out");

int N,sol;
bool viz[100010];
vector <int> Muchie[100010];

void citire() {

    ifstream in("dfs.in");
    int x,y,M,i;
    in>>N>>M;
    for(i=1;i<=N;i++) {
        in>>x>>y;
        Muchie[x].push_back(y);
        Muchie[y].push_back(x);
    }
    in.close();

}

void Dfs(int nod) {

    int vecin,i;
    viz[nod]=1;
    for(i=0;i<Muchie[nod].size();i++) {
        vecin=Muchie[nod][i];
        if(viz[vecin]==0)
            Dfs(vecin);
    }
}

int main() {

    citire();
    for(int i=1;i<=N;i++){
        if(viz[i]==0){
            sol++;
            Dfs(i);
        }
    }
    out<<sol<<'\n';
    out.close();
    return 0;


}