#include <fstream>
#include <queue>
#define NMAX 1001
using namespace std;

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

int n, m, a[NMAX][NMAX], viz[NMAX * NMAX], nr=0;

void citire(){
    fin>>n>>m;
    for(;m;m--){
        int i, j;
        fin>>i>>j;
        a[i][j] = a[j][i] = 1;
    }
}
void DFS(int x){
    viz[x] = 1;
    for(int i=1; i<=n; i++){
        if(a[x][i] and !viz[i])
            DFS(i);
    }
}


int main(){
    citire();
    for(int i=1; i<=n; i++){
        if(!viz[i]){
            nr++;
            DFS(i);
        }
    }
    fout<<nr;


    return 0;
}