#include <bits/stdc++.h>
using namespace std;

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

vector<int> L[100005];
bool viz[100005];

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

int main(){
    int n, m;
    fin >> n >> m;
    for(int i = 1; i <= n; i++){
        int a, b;
        fin >> a >> b;
        L[a].push_back(b);
        L[b].push_back(a);
    }
    int cc = 0;
    for(int i = 1; i <= n; i++){
        if(!viz[i]){
            cc++;
            dfs(i);
        }
    }
    fout << cc;
    return 0;
}