#include <bits/stdc++.h>
#include <iostream>
using namespace std;
const int maxNr = 1e6;
bool viz[maxNr];
vector<int> v[maxNr];

void dfs(int nod){
	viz[nod]=1;
	for(auto it: v[nod]){
		if(!viz[it])
			dfs(it);
	}
}

int main(){

	int n,m;
	ifstream f("dfs.in");
	f >> n >>m;
	for(int i=0;i<n;i++){
		int x,y;
		f >> x >> y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	f.close();
	int nrCompConexe=0;
	for(int i=1;i<=n;i++){
		if(!viz[i]){
			nrCompConexe++;
			dfs(i);
		}
	}
	ofstream g("dfs.out");
	g << nrCompConexe;
	g.close();
    //linux output debug.
    cout << '\n';
    return 0;
}