#include <iostream>
#include <fstream>

using namespace std;

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

const int N = 100003;
const int M = 200001;
bool viz[N];
int vf[2 * M], lst[N], urm[2 * M];
int nr, n, m;

void dfs(int x) {
	viz[x] = true;
	int y;
	for (int p = lst[x]; p != 0; p = urm[p]) {
		y = vf[p];
		if (!viz[y]) {
			dfs(y);
		}
	}
}

void adauga(int x, int y) {
	vf[++nr] = y;
	urm[nr] = lst[x];
	lst[x] = nr;
}

struct comp {
	int x, y;
}v[N];

int main() {
	in >> n >> m;
	int cnt = 0;
	for (int i = 1; i <= m; i++) {
		in >> v[i].x >> v[i].y;
		adauga(v[i].x, v[i].y);
		adauga(v[i].y, v[i].x);
	}
	for (int i = 1; i <= n; i++) {
		if (viz[i] == false) {
			dfs(i);
			cnt++;
		}
	}
	out << cnt;
	return 0;
}