#include <cstdio>
#define rep(i,n) for(int i=0;i<n;++i)
using namespace std;

const int nmax=100010;
int par[nmax],rnk[nmax];
void init(int n){rep(i,n) par[i]=i,rnk[i]=0;}
int find(int x){return (par[x]==x)?x:par[x]=find(par[x]);}
void unite(int a,int b){
	a=find(a),b=find(b);
	if(a==b) return;
	if(rnk[a]<rnk[b])
		par[a]=b;
	else{
		par[b]=a;
		if(rnk[a]==rnk[b]) rnk[a]++;
	}
}

int main(void){
	int n,m;
	scanf("%d%d",&n,&m);
	init(n);
	while(m--){
		int a,b;
		scanf("%d%d",&a,&b);
		unite(a,b);
	}
	int ans=0;
	rep(i,n) ans+=(i==par[i]);
	printf("%d\n",ans);
	return 0;
}