#include <iostream>
#include<fstream>
#include<vector>
#include<queue>
using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

vector <bool> viz(100003, false);
queue <int> lista[100003];
void DFS(int nod, int N) {
	viz[nod] = true;
			while (lista[nod].size() >= 1) {
				int temp = lista[nod].front();
				lista[nod].pop();
				if (viz[temp] == false)
					DFS(temp, N);

			}
}
int main()
{
	int N, M;
	f >> N >> M;
	for (int i = 0; i < M; i++) {
		int x, y;
		f >> x >> y;
		lista[x].push(y);
		lista[y].push(x);
	}
	
	/*for (int i = 1; i <= N; i++) {
		while (lista[i].size() > 0)
			cout << lista[i].front() << ' ', lista[i].pop();
		cout << endl;
	}
	*/
		
	int cnt = 0;
	for(int i=1;i<=N;i++)
		if (viz[i] == false) {
			cnt++;
			DFS(i, N);
		}
	g << cnt;
	
	//DFS(1, N);
	f.close();
	g.close();
	return 0;
}