#include <fstream>
#include <vector>
#define nmax 100002
using namespace std;

ifstream f("dfs.in");
ofstream g1("dfs.out");

vector <int> g[nmax];
int n,m,x,y,i,cnt;
bool viz[nmax];

void citire ()
{
	f>>n>>m;
	for (i=1; i<=m; i++)
	{
		f>>x>>y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	f.close ();
}

void dfs (int x)
{
	for (i=1; i<=g[x].size(); i++)
		if (!viz[g[x][i]])
			dfs (g[x][i]);
}

void descompune ()
{
	for (i=1; i<=n; i++)
		if (!viz[i])
		{
			dfs(i);
			cnt++;
		}
}

void afisare ()
{
	g1<<cnt;
	g1.close ();
}

int main ()
{
	citire ();
	descompune ();
	afisare ();
	return 0;
}