#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

//std::ifstream f("graful.txt");
//std::ofstream g("graful.out");
std::ifstream f("dfs.in");
std::ofstream g("dfs.out");

int start = 0;
class graf
{
	int nrvf, nrmuchii;
	std::vector<int>* vecini;

public:
	graf(bool orientat);

	void verifvecini();

	void BFS();
	void DFS(int nod, bool* viz);
	void cadruDFS();

	~graf()
	{
		delete []vecini;
	}
};

graf::graf(bool orientat)
{
	f >> nrvf >> nrmuchii;
	if(start == 1)	// daca avem de citit un nod de start...
		f >> start;

	vecini = new std::vector<int>[nrvf + 1];
	if (orientat == true)
		for (int i = 0; i < nrmuchii; i++)
		{
			int x, y;
			f >> x >> y;
			vecini[x].push_back(y);
		}
	else
		for (int i = 0; i < nrmuchii; i++)
		{
			int x, y;
			f >> x >> y;
			vecini[x].push_back(y);
			vecini[y].push_back(x);
		}
}

void graf::verifvecini()
{
	for (int i = 1; i <= nrvf; i++)
	{
		std::cout << "\n  vecinii lui " << i << " :  ";
		for (unsigned int j = 0; j < vecini[i].size(); j++)
			std::cout << vecini[i][j] << " ";
	}
}

void graf::BFS()
{
	int* dist = new int[nrvf + 1]{ 0 };	// initializam distantele cu 0 (le decrementam ulterior)
	std::queue <int> qBFS;	  // coada pt BFS
	qBFS.push(start);
	dist[start] = 1;

	while (!qBFS.empty())
	{
		const int nod = qBFS.front();
		for (unsigned int i = 0; i < vecini[nod].size(); i++)
		{
			const int nod_urm = vecini[nod][i];
			if (dist[nod_urm] == 0)
			{
				qBFS.push(nod_urm);
				dist[nod_urm] = dist[nod] + 1;
			}
		}

		qBFS.pop();
	}

	for (int i = 1; i <= nrvf; i++)
		g << dist[i] - 1 << " ";

	delete [] dist;
}

void graf::DFS(int nod, bool* viz)
{
	viz[nod] = true;
	for (int i = 0; i < vecini[nod].size(); i++)
	{
		const int nod_urm = vecini[nod][i];
		if (!viz[nod_urm])
			DFS(nod_urm, viz);
	}
}

void graf::cadruDFS()
{
	int conexe = 0;
	bool* viz = new bool[nrvf + 1]{ 0 };
	for (int i = 1; i <= nrvf; i++)
		if( ! viz[i] )
		{
			conexe++;
			DFS(i, viz);
		}
	g << conexe;
}

int main()
{
	start = 1;		// afirmam ca citim si un nod de start;
	graf g(false);
	g.cadruDFS();

	return 0;
}