#include<iostream>
#include<vector>
#include<stdio.h>
using namespace std;
bool viz[100001];
vector <int> v[100001];  
void df(int nod)
{          
	viz[nod]=true;
	for(int i=0;i<v[nod].size();i++)
	{
		if(viz[v[nod][i]]==false)
		{
			df(v[nod][i]);
		}
	}
}
int conex(int n)
{
	int nr=0;
	for(int i=1;i<=n;i++)
		if(viz[i]==false)
		{
			nr++;
			df(i);
		}
	return nr;
}
int main()
{
    int n,m;
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
    scanf("%d %d", &n, &m);
	int x,y;
	for(int i=1;i<=m;++i)
	{
		scanf("%d %d", &x, &y);
		v[x].push_back(y);
		v[y].push_back(x);
	}
	printf("%d", conex(n));
    return 0;
}