#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int a[1005][1005], n, m, viz[1005], c,x,y,i,j;
void citire()
{
	
	f >> n >> m;
	while(f>>x>>y)
	{
		a[x][y] = 1;
		a[y][x] = 1;
	}
	
}
void DFS(int nod)
{
	int i;
	viz[nod] = 1;
	for (i = 1; i <= n; i++) 
		if (viz[i] != 1 && a[nod][i] == 1)
		{
			viz[i] = 1;
			DFS(i);
		}
}
int main()
{
	citire();
	int i;
	for (i = 1; i <= n; i++) 
		if (viz[i]==0) 
		{ c++; 
			DFS(i); }
	g << c;
}