#include<bits/stdc++.h>
using namespace std;
long long n,m,x,y,fa[50005],as;
long long f(long long x){
    if(fa[x]!=x){
        fa[x]=f(fa[x]);
    }
    return fa[x];
}
int main(){
    freopen("religion.in","r",stdin);
    freopen("religion.out","w",stdout);
    scanf("%lld%lld",&n,&m);
    for(long long i=1;i<=n;i++){
        fa[i]=i;
    }
    for(long long i=1;i<=m;i++){
        scanf("%lld%lld",&x,&y);
        fa[f(x)]=f(y);
    }
    for(long long i=1;i<=n;i++){
        if(fa[i]==i){
            as++;
        }
    }
    printf("%lld",as);
    return 0;
}