#include<iostream>
#include<cstdio>
using namespace std;
const int maxn=50010;
int n,m,f[maxn],a,b,ans;
void make_set()
{
	for(int i=1;i<=n;i++)
		f[i]=i;
}
int find(int x)
{
	if(x==f[x])
		return x;
	f[x]=find(f[x]);
	return f[x];
}
void merge(int x,int y)
{
	int f1=find(x);
	int f2=find(y);
	f[f1]=f2;
}
int main()
{
	freopen("religion.in","r",stdin);
	freopen("religion.out","w",stdout);
	cin>>n>>m;
	make_set();
	for(int i=1;i<=m;i++)
	{
		cin>>a>>b;
		merge(a,b);
	}
	for(int i=1;i<=n;i++)
		if(f[i]==i)
			ans++;
	cout<<ans<<endl;
	return 0;
}