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

using namespace std;

#define NMAX 100002

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

vector <int> vecini[NMAX];

int n, m, conexe = 0;
bool wasCrossed[NMAX] = { false };

void Read()
{
	fin >> n >> m;
	int x, y;
	for (int i = 0; i < m; i++)
	{
		fin >> x >> y;
		vecini[x].push_back(y);
		vecini[y].push_back(x);
	}
}

void DFS(int node)
{
	wasCrossed[node] = true;
	for (unsigned int i = 0; i < vecini[node].size(); i++)
	{
		if (!wasCrossed[vecini[node].at(i)])
		{
			DFS(vecini[node].at(i));
		}
	}
}

int main()
{
	Read();
	for (int i = 1; i <= n; i++)
	{
		if (!wasCrossed[i])
		{
			conexe++;
			DFS(i);
		}
	}
	fout << conexe;
	return 0;
}