#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;


int L[10001][10001];
int viz[10001];

int n, m;

void DFS(int x){

    viz[x]=1;

    for(int i=1; i<=n; i++){
        if(L[x][i] && !viz[i]){
            viz[i]=1;
            DFS(i);
        }
    }

}


int main(){
    ifstream cin("dfs.in");
    ofstream cout("dfs.out");

    cin>>n>>m;

    int comp=0;

    for(int i=0; i<m; i++){
        int x, y;
        cin>>x>>y;
        L[x][y]=L[y][x]=1;
    }

    for(int i=1; i<=n; i++){
        while(!viz[i]){
            DFS(i);
            comp++;
        }
    }

    cout<<comp;

    return 0;
}