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

ifstream fin("dfs.in");
int v[10000];
int m[1000][1000];
int n,muchii;
void dfs(int nod){
    v[nod] =1;
    for(int i=1; i<=n; i++){
        if (m[nod][i] == 1 && v[i]==0){
            dfs(i);
        }
    }
}

int main()
{
    fin>>n>>muchii;
    
    for (int i =0; i<muchii; i++){
        
        int x, y;
        fin>>x>>y;
        m[x][y] = 1;
        m[y][x] =1;
    }
    int cnt=0;
    for (int i=1; i<=n; i++){
        if (v[i] == 0){
            dfs(i);
            cnt++;       
        }
    }
    cout<<cnt;

    return 0;
}