#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;

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

int N, M;
map<int, vector<int>> G;
map<int, bool> visited;

void Read()
{
	fin >> N >> M;
	for (int i = 1; i <= N; i++)
		G.insert({ i, vector<int>() });

	for (int i = 0; i < M; i++)
	{
		int x, y;
		fin >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void DFS(int node)
{
	visited[node] = true;
	for (auto child : G[node])
		if (!visited[child])
			DFS(child);
}

int main()
{
	Read();

	int components = 0;
	for (int i = 1; i <= N; i++)
		if (!visited[i])
		{
			components++;
			DFS(i);
		}

	fout << components;

	return 0;
}