#include <fstream>
#include <vector>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector<int> g[100001];
int n, m;
bool verificare[100001];

void dfs(int nod)
{
	verificare[nod] = 1;
	for (int i = 0; i < g[nod].size(); i++)
		if (verificare[g[nod][i]] == 0)
			dfs(g[nod][i]);

}

int main()
{
	int x, y;
	fin >> n >> m;
	for (int i = 1; i <= m; i++)
	{
		fin >> x >> y;
		g[x].push_back(y);
		g[y] .push_back(x);
	}

	int ct = 0;
	for(int i=1;i<=n;i++)
		if (verificare[i] == 0)
		{
			ct++;
			dfs(i);
		}
	fout << ct;
	
	return 0;
}