#include <iostream>
#include <fstream>
#include <vector>
#include <utility> 
#include <queue>

int visited[200002];

using namespace std;

void dfs(vector <vector <int> > const vecini, vector<int>& parent, int nod) {
	visited[nod] = 1;
	for (unsigned int i = 0 ; i < vecini[nod].size(); ++i) {
		if (visited[vecini[nod][i]] == 0) {
			parent[vecini[nod][i]] = nod;
			dfs(vecini, parent, vecini[nod][i]);
		}
	}
}
int main() {

	int n, m;
	ifstream in("dfs.in");
	ofstream out("dfs.out");
	in >> n >> m;
	int x,y;
	vector< vector <int> > vec (n+1, vector<int>());
	for (int i = 0; i < n; ++i){
		in >> x >> y;
		vec[x].push_back(y);
		vec[y].push_back(x);
	}
	vector<int> parent(n+1, -1);
	int comp_con = 0;
	for (int i = 1; i <= n; ++i)
		if (visited[i] == 0) {
			dfs(vec, parent, i);
			++comp_con;
		}
	out << comp_con << "\n";
}