#include <iostream>

using namespace std;

int search(int x)
{
	if (f(x) != x)
		f(x) = search(f(x))
	return f(x);
}
int marge(int x,int y)
{
	f(search(x)) = search(y);
}
int main()
{
	freopen("religion.in","r",stdin);
	freopen("religion.out","w",stdout);
	int n,m;
	cin >> n >> m;
	int *f[] = new int [n];
	for (int i = 0;i < n;++i)
		f[i] = i;
	int x,y;
	for (int i = 0;i < m;++i)
	{
		cin >> x >> y;
		marge(x,y);
	}
	int num = 0;
	for (int i = 0;i < n;++i)
		if (f(x) = x)
			++num;
	cout << num;
	return 0;
}