#include<bits/stdc++.h>
using namespace std;
int n,m,fa[50010],sum;
void init(){
	for(int i=1;i<=n;i++) fa[i]=i;
	return ;
}
int Find(int x){
	if(fa[x]!=x) fa[x]=Find(fa[x]);
	return fa[x];
}
void Union(int x,int y){
	int a=Find(x),b=Find(y);
	if(a!=b) fa[b]=a;
	return ;
}
int main(){
    freopen("religion.in","r",stdin);
    freopen("religion.out","w",stdout);
	scanf("%d%d",&n,&m);
	init(); 
	int x,y;
	for(int i=1;i<=m;i++){
	    scanf("%d%d",&x,&y);
        Union(x,y);
	}
	for(int i=1;i<=n;i++){
	    if(Find(i)==i){
            sum++;
        }
    }
	printf("%d",sum);
	return 0;
}