#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,f[1000001];
vector <int>G[100001];
void dfs(int nod){
    f[nod]=1;
    for(size_t i=0;i<G[nod].size();i++){
        int vecin=G[nod][i];
        if(f[vecin]==0)
            dfs(vecin);
    }
}
int main(){
    fin>>n>>m;
    for(int ll=1;ll<=m;ll++){
        int i,j;
        fin>>i>>j;
        G[i].push_back(j);
        G[j].push_back(i);
    }
    int cnt=0;
    for(int i=1;i<=n;i++){
        if(f[i]==0)
            cnt++,dfs(i);
    }
    fout<<cnt;
    return 0;
}