printTree($W);	# just dumps HOHOH - could use data::dumper - removed
remove1($W,2);	# ie remove layer 2 ( counting from 1 )
print "--------------------\n";
printTree($W);

sub remove1
{
	my($refToHash)=shift;
	my($stage)=shift;
	
	foreach $a (keys %{$refToHash})
	{
		if($depth==$stage-1) # then we've hit the level before the level to be removed/
		{
			print "removing $a\n";
			foreach $b (keys %{$refToHash->{$a}})
			{
				$refToHash->{$b} = $refToHash->{$a}->{$b};
				delete($refToHash->{$a});
			}
		}
		else
		{
			$depth++;
			remove1($refToHash->{$a},$stage);
			$depth--;
		}
	}
}