#include <fstream>
#include <vector>
using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,k,i,p,m,x,y,nr=0;
int viz[100010];
long long s;
vector <int>l[100010];
void dfs(int nod){
    int i;
    viz[nod]=1;
    for(i=0;i<l[nod].size();i++){
        if(viz[l[nod][i]]==0){
            dfs(l[nod][i]);
        }
    }

}
int main(){
    fin>>n>>m;
    for(i=1;i<=n;i++){
        fin>>x>>y;
        l[x].push_back(y);
        l[y].push_back(x);
    }
     for(i=1;i<=n;i++){
            if(viz[i]==0){
                dfs(i);
                nr++;
            }
     }
     fout<<nr;
}