#include <stdio.h>
#include<vector>
using namespace std;

const int N=100001;
int n,m,c;
vector <int> a[N];
int b[N];
void dfs(int i)
{
	b[i]=1;int k;
	for (int j=0;j<a[i].size();j++)
	{
		k=a[i][j];
		if (b[k]==0)
			dfs(k);
	}
}
int main()
{
	int x,y;
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;i++)
	{
		scanf("%d%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	for (int i=1;i<=n;i++)
	{
		if (b[i]==0)
		{
			c=c+1;
			dfs(i);
		}
	}
	printf("%d",c);
}