#include <queue>
#include <vector>
#include <fstream>
#include <cstdlib>
#include <iterator>
#include <algorithm>
#define N_MAX 100011

using namespace std;

bool was[N_MAX];
vector< int > G[N_MAX];
vector< int >::const_iterator it, iend;

inline void DFS( int x )
{
	was[x]=true;
	vector<int>::const_iterator it=G[x].begin(), iend=G[x].end();
	
	for( ; it < iend; ++it )
		if( false == was[*it] )
			DFS(*it);
}
int main()
{
	int N, M, x, y, count=0;
	ifstream in( "dfs.in" );
	ofstream out( "dfs.out" );

	for( in>>N>>M; M; --M )
	{
		in>>x>>y;
		G[x].push_back( y );
		G[y].push_back( x );
	}
	for( x=1; x <= N; ++x )
		if( false == was[x] )
		{
			DFS(x);
			++count;
		}
	out<<count<<'\n';

	return EXIT_SUCCESS;
}