#include<bits/stdc++.h>
using namespace std;
int n,sum=0;int m=1,f[500003];
int find(int x){return f[x]==x ? x:find(f[x]);
}
int main()
{
	freopen("religion.in","r",stdin);
	freopen("religion.out","w",stdout);
	cin>>n>>m;
	int v=n;
	int a,b;
	for(int i=1;i<=n;i++)f[i]=i;
	for(int i=1;i<=m;i++)
	 {
	 	scanf("%d%d",&a,&b);
	 	int s=find(a),e=find(b);
	 	if(s!=e)
	 	{
	 		f[s]=e;
	 		v--;
	 		if(v==1)break;
		 }
	 }
	cout<<v;
	return 0;
}