#include<fstream.h>
#include<vector>

using namespace std;

vector < vector <int> > lista;

int sel[100001],n,m,v=0;
void DFS (int i)
{
	int j;
	sel[i]=1;
	int size = lista[i].size();
	for (j= 0;j < size;j++)
	{
		if(sel[lista[i][j]]==0)
			DFS(lista[i][j]);
	}
}
int main()
{
	int i,j;
	ifstream f ("dfs.in");
	ofstream g ("dfs.out");
	f>>n>>m;
	vector <int > temp;
	for( int i = 0; i <= n; ++i)
		lista.push_back( temp);
	while (f>>i>>j)
	{
		lista[i].push_back(j);
		lista[j].push_back(i);
		
	}
	for(i=1;i<=n;i++)
	{
		if (sel[i]==0)
		{
			v++;
			DFS(i);
		}
	}
	g<<v;
	f.close();
	g.close();
	return 0;
}