#include <bits/stdc++.h>
#define NMax 100005

using namespace std;

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

vector <int>a[NMax];
int n,m,comp;
bool viz[NMax];


void citire(){
    fin>>n>>m;
    for(int i=1,x,y;i<=n;i++){
        fin>>x>>y;
        a[y].push_back(x);
        a[x].push_back(y);
    }
}

void dfs(int nod){
    int q;
    viz[nod]=1;
    for(int i=0;i<a[nod].size();i++)
        if(viz[a[nod][i]]==0)
            dfs(a[nod][i]);
}

void rezolvare(){
    citire();
    for(int i=1;i<=n;i++){
        if(viz[i]==0){
            dfs(i);
            comp++;
        }
    }
    fout<<comp;
}

int main()
{
    rezolvare();
    return 0;
}