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

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

vector <int> G[100001];
bool s[100001];

int m, n, nrc;
void Read();
void DF(int nod);

int main()
{
	Read();
	for (int i = 1; i <= n; ++i)
		if (!s[i])
		{
			nrc++;
			DF(i);
		}
	fout << nrc << '\n';
	fin.close();
	fout.close();
	return 0;
}

void Read()
{
	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);
	}
}

void DF(int nod)
{
	s[nod] = true;
	for ( int i = 0; i < G[nod].size(); ++i )
		if ( !s[G[nod][i]] )
		{
			s[G[nod][i]] = true;
			DF(G[nod][i]);
		}
}