#include <bits/stdc++.h> 
#include <fstream>
#include <vector>
using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

const int NLIM =100005;
vector < int > Muchii[NLIM];

int N,M;
bool vizitat [NLIM];
int insule =0;

void DFS (int Nod)
{
	vizitat[Nod] = true;
	for(unsigned int i=0; i<=Muchii[Nod].size(); i++)
	{
		int Vecin = Muchii[Nod][i];
		if(!vizitat[Vecin]) 
		  DFS(Vecin);
	}
}

void Citire()
{
	fin>>N>>M;
	for (int i=1;i<=M;i++)
	{
		int x,y;
		fin>>x>>y;
		Muchii[x].push_back(y);
		Muchii[y].push_back(x);
	}
	for (int i=1;i<=M;i++)
	{
		if(!vizitat[i])
		{
			insule +=1;
			DFS(i);
		}
		   
	}
	fout<<insule<<endl;
}

int main()
{
	Citire();
	return 0;
}