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

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

vector <int> v[100001];
int viz[100001];

 void DFS(int nod)
{
	viz[nod] = 1;
	
	for (int i = 0; i < v[nod].size(); i++)
		
		if (!viz[v[nod][i]])
			DFS(v[nod][i]);
}

 int main()
{
	int n, m, x, y, i, nr = 0;
	f >> n >> m;
	
	for (i = 1; i <= m; i++)
	{
		f >> x >> y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	
	for (i = 1; i <= n; i++)
		if (viz[i] != 1)
		{
			DFS(i);
			nr++;
		}
	g << nr;
}