$tophash{$value1}{$value2} = [$a, $b, $c, $d];

foreach $key (sort keys %tophash) 
{
	$value1 = $key;
	print "$value1";

	foreach $subkey (sort keys %{$tophash{$value1}}) 
	{
		$value2 = $subkey;
		
		foreach $subsubkey (sort %{$tophash{$value}{$value2}} ) 
		{
			print "$subsubkey";
		}
	}
}