#include <iostream>
#include<fstream>
#include<vector>
#include<algorithm>
#include<map>

using namespace std;

vector<int> *graf = new vector<int>[100005];
int *visit = (int*)calloc(100003, sizeof(int));
vector<int> parcdfs;

int ctc = 0;

void explorare(int nod) {

	visit[nod] = -1; //in curs de prelucrare
	unsigned int i;
	int index;
	for ( i = 0; i < graf[nod].size(); i++)
	{
		int copil = graf[nod][i];
		if ( visit[copil] == 0)
			explorare(copil);

	}

	visit[nod] = 1;
	//parcdfs.push_back(nod);

}


void solve(int n) {
	for (int i = 1; i <= n; i++)
	{
		if (visit[i] == 0)
		{
			ctc++;
			explorare(i);

		}
	}

}
int main()
{
	ifstream f("dfs.in");
	ofstream g("dfs.out");
	int n, m;
	f >> n >> m;
	int i;
	int x, y;

	for (i = 0; i < m; i++)
	{
		f >> x >> y;
		graf[x].push_back(y);
		graf[y].push_back(x);
	}
	solve(n);
	g << ctc;
}