#include <fstream>
#include <vector>
#define DIM 100010

using namespace std;

int cnt = 0;
int n, m;
vector <int> graf[DIM];
bool viz[DIM];

void Read()
{
	ifstream fin("dfs.in");
	fin >> n >> m;
	int x, y;
	for (int i = 1;i <= m;++i)
	{
		fin >> x >> y;
		graf[x].push_back(y);
		graf[y].push_back(x);
	}
	fin.close();
}

void DFS(int nod)
{
	viz[nod] = true;
	for (int i = 0;i < graf[nod].size();++i)
	{
		if (!viz[graf[nod][i]])
			DFS(graf[nod][i]);
	}
}

void Solve()
{
	for (int i = 1;i <= n;++i)
		if (!viz[i])
		{
			++cnt;
			DFS(i);
		}
}

void Write()
{
	ofstream fout("dfs.out");
	fout << cnt << "\n";
	fout.close();
}

int main()
{
	Read();
	Solve();
	Write();
	return 0;
}