#include<fstream>
using namespace std;
int n,m,x[10000][10000],viz[10000],res;
ifstream f("dfs.in");
ofstream g ("dfs.out");
void df(int node)
{
	viz[node]=1;
	for(int i=1;i<=n;++i)
	{
		if(x[node][i] && viz[i]==0)
		{
			df(i);
		}
	}
}
int main()
{
	f>>n>>m;
	int aux1,aux2;
	for(int i=0;i<m;++i)
	{
		f>>aux1>>aux2;
		x[aux1][aux2]=1;
		x[aux2][aux1]=1;
	}
	for(int i=1;i<=n;++i)
	{
		if(viz[i]==0)
		{
			df(i);
			res++;
		}
	}
	g<<res;
	return 0;
}