#include <bits/stdc++.h>
using namespace std;
int k,m,n,a,b;
vector <int> v[100010];
bool u[100010];

void dfs(int q){
u[q]=1;
for (int i=0;i<v[q].size();i++){
    if (!u[v[q][i]]) dfs(v[q][i]);
}
}
int main(){
    ifstream in("dfs.in");
    ofstream out("dfs.out");
in>>n>>m;
for (int i=1;i<=n;i++){
    in>>a>>b;
    v[a].push_back(b);
    v[b].push_back(a);
}
for (int i=1;i<=n;i++){
    if (!u[i]){
            k++;
        dfs(i);

    }
}
out<<k;
return 0;
}