//
//  main.cpp
//  DFS-componente_conexe
//
//  Created by Tereza Oprea on 14/10/2018.
//  Copyright © 2018 Tereza Oprea. All rights reserved.
//

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

vector <int> v [200010];

int viz[200010];

int n, m;

void dfs (int nod){
    
    viz[nod] = 1;
    for (auto it : v[nod])
        if (viz[it] == 0)
            dfs(it);
        
}

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