#include <fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int viz[100002], n;

void dfs(int rad)
{
	viz[rad] = 1;
	for (int i = 1; i <= n; i++)
		if (viz[i] == 0) {
			dfs(i);
		}
}


int main()
{ 
	int k, i, x, y, nr=0, m;
	fin >> n >> m;
	for(int i=0;i<m;++i)
	{
		fin >> x >> y;
		vec[x][y] = vec[y][x] = 1;
	}
	for (i = 1; i <= n; i++)
	{
		if (viz[i] == 0)
		{
			nr++;
			dfs(i);
		}
	}
	fout << nr;
	fin.close();
	fout.close();
	return 0;
}