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

int N, M;

vector<bitset<100001> >g;
bitset<100001> viz;

void dfs(int n)
{
	viz[n] = true;

	for (int i = 1; i <= N; i++)
		if (!viz[i] && g[n][i])
			dfs(i);
}

int main()
{
	ifstream in("dfs.in");

	in >> N >> M;
	g.resize(N + 1);

	for (int i = 1; i <= M; i++)
	{
		int x, y;
		in >> x >> y;

		g[x][y] = g[y][x] = true;
	}

	int nr = 0;

	for (int i = 1; i <= N; i++)
	{
		if (!viz[i])
		{
			nr++;
			dfs(i);
		}
	}

	ofstream out("dfs.out");
	out << nr;
}