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

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

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

void read()
{
	int x, y;
	in >> n >> m;
	for(int i = 0; i < m; ++i)
	{
		in >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
}

void dfs(int s)
{
	f[s] = 1;
	for(auto i : g[s])
		if(!f[i]) dfs(i);
}

int main()
{
	read();
	for(int i = 1; i <= n; ++i)
		if(!f[i]) k++, dfs(i);
	out << k;
	return 0;
}