#include <fstream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m;
bool viz[100101];

vector<int> L[100101];

void dfs(int nod){
    viz[nod]=true;
    for(register int i=0;i<L[nod].size();i++){
        if(!viz[L[nod][i]])
            dfs(L[nod][i]);
    }
}

int main(void){
    register int i,j,x,y;

    f>>n>>m;
    for(i=1;i<=n;i++){
        f>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }

    int nr=0;
    for(i=1;i<=n;i++)
        if(!viz[i])
            nr++,dfs(i);

    g<<nr;
    f.close();
    g.close();
    return 0;
}