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

using namespace std;

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

const int NLIM = 100005;

int N, M;
bool vizitat[NLIM];
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] == false)
			dfs(vecin);
	}
}

int citire() 
{
	int insule = 0;

	fin >> N >> M;

	for (int i = 1; i <= N; 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] == false)
			dfs(i), insule++;

	return insule;
}

int main()
{
	fout << citire();

	fin.close();
	fout.close();
	return 0;
}