#include <iostream>
#include <vector>
#include <fstream>
using namespace std;
const int nlim=100000;
unsigned int n,m,rev=0;
bool viz[nlim]={false};
ifstream f("dfs.in");
ofstream g("dfs.out");
vector <unsigned int > muchii[nlim];
void dfs (int revista)
	{
		viz[revista]= true;
		for (unsigned i=0; i<muchii[revista].size (); i++)
			{
				unsigned int vec=muchii[revista][i];
				if (!viz[vec])
					dfs (vec);
			}
	}
void citire()
{	
	f>>n>>m;
	for (unsigned i=1; i<=m; i++)
		{
			int x,y;
			f>>x>>y;
			muchii[x].push_back(y);
			muchii[y].push_back(x);
		}
	for (unsigned i=1; i<=n;i++)
		{
			if (!viz[i])
				{
					rev++;
					dfs(i);
				}
		}
}
int main() 
{			
	citire();
	g<<rev;
	f.close();
	g.close();
	return 0;
}