#include<stdio.h>
#include<string.h>
#include<vector>


using namespace std;


int nr,x,y,i,m,n;
bool ok[1000001];
vector <int> a[100001];


void dfs(int q)
{
	vector <int>::iterator it;
	
	ok[q]=true;
	for (it=a[q].begin();it!=a[q].end();it++)
		if(!ok[*it]) dfs(*it);
}

int main()

{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	
	scanf("%d%d",&n,&m);
	
	for (i=1;i<=m;i++)
	{
		scanf("%d%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	
	memset(ok,false,sizeof(bool));
	
	for (i=1;i<=n;i++)
	{
		if (ok[i]==false)
		{
			nr++;
			dfs(i);
		}
	}
	
	printf("%d\n",nr);
	
	return 0;
}