#include<cstdio>
#include<set>
#define syy myson
using namespace std;
int n,m,fa[50010],num[50010],ans,i;
int find(int x)
{
	if(fa[x]!=x)fa[x]=find(fa[x]);
	return fa[x];
}
int Main()
{
	freopen("religion.in","r",stdin);freopen("religion.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++)fa[i]=i;
	for(i=1;i<=m;i++)
	{
		int a,b;
		scanf("%d%d",&a,&b);
		if(find(a)!=find(b))
		  fa[find(b)]=fa[find(a)];
	}
	for(i=1;i<=n;i++)
	{
		fa[i]=find(i);
		num[fa[i]]++;
	}
	for(i=1;i<=n;i++)
	  if(num[i])ans++;
	printf("%d",ans);
	return 0;
}
int main(){;}
int syy=Main();