#include <bits/stdc++.h>
using namespace std;
const int N=100010;
int n,m,fa[N],flag[N],ret;
int find(int x)
{
	if (fa[x]==x) return x;
	else return fa[x]=find(fa[x]);
}
int main() {
	freopen("religion.in","r",stdin);
	freopen("religion.out","w",stdout);
	cin>>n>>m;
	for (int i=1;i<N;i++)
	{
		fa[i]=i;
	}
	while (m--)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		int fx=find(fa[x]),fy=find(fa[y]);
		if (fx!=fy) fa[fx]=fy;
	} 
	/*
	for (int i=1;i<=n;i++)
	{
		cout<<fa[i]<<endl;
	}
	*/
	for (int i=1;i<=n;i++)
	{
		if(!flag[find(fa[i])])
		{
			flag[find(fa[i])]=1;
			ret++;
		}
	}
	cout<<ret;
}