#include<bits/stdc++.h>
using namespace std;
int p[50005];
int n,m;
int find(int x){
    return p[x]=(p[x]==x?p[x]:find(p[x]));
}
void join(int a,int b){
    if(find(a)!=find(b)){
        p[find(a)]=find(b);
        n--;
    } 
}
int main(){
    freopen("religion.in","r",stdin);
    freopen("religion.out","w",stdout);
    cin>>n>>m;
    for(int i=1;i<=n;i++) p[i]=i;
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        join(a,b);
    }
    cout<<n<<endl;
    return 0;
}