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

ifstream f("dfs.in");
ofstream g("dfs.out");
int a[10000][10000],T[1000];
void df(int x,int n){
    for(int i =1;i<= n;i++){
        if(T[i] == 0 && a[x][i] == 1)
            T[i] = 1;
            df[i];
    }

}
int main()
{   int n,m,s;
    f>>n>>m;
    int x,y;
    for(int i = 1;i<= m;i++){
        f>>x>>y;
        a[x][y] = 1;
        a[y][x] = 1;
    }
    int nr = 0;
    for(int i = 1;i<= n;i++){
        if(T[i] == 0){
            T[i] = 1;
            df(i,n);
            nr++;
        }
    }
    g << nr;
    return 0;
}