#include <vector>
#include <fstream>
#include <cstdlib>
#define N_MAX 100011

using namespace std;
bool was[N_MAX];
vector< int > G[N_MAX];
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( void )
{
	int N, M, x, y;
	ifstream in( "dfs.in" );
	for( in>>N>>M; M; --M )
	{
		in>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	for( y=0, x=1; x <= N; ++x )
		if( false == was[x] )
		{
			++y;
			DFS(x);
		}
	ofstream out( "dfs.out" );
	out<<y<<'\n';
	return EXIT_SUCCESS;
}