#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

const int NLIM{ 100005 };
int N, M;
int vizitat[NLIM];
int insule{ 0 }; 


vector <int> Muchii[NLIM];

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 <= N; i++)
	{
		if (!vizitat[i])
		{
			insule += 1;
			DFS(i);
		}
	}
}

int main()
{
	Citire();
	fout << insule << endl;
	return 0;
}