#include <fstream>

using namespace std;

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

int a[10000][10000], viz[10000], n, m;

int df(int nod){
    viz[nod]=1;
    for(int i=1; i<=n; i++)
        if(viz[i]==0 && a[nod][i]==1) df(i);
}

int main()
{
    int x, y, k=0;

    cin>>n>>m;

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

    for(int i=1; i<=n; i++)
    if(viz[i]==0) k++, df(i);

    cout<<k;

    return 0;
}