sub sorter
{
$a = shift;
$b = shift;

	if($hashYear{$a} < $hashYear{$b})
	{
		return $a;
	}
	elsif($hashYear{$a} == $hashYear{$b})
	{
		if($hashMonth{$a} < $hashMonth{$b})
		{
			return $a;
		}
		elsif($hashMonth{$a} == $hashMonth{$b})
		{
			if($hashDay{$a} < $hashDay{$b})
			{
				return $a;
			}
		}
	}
	else
	{
	#b is greater than a (or, in a rare case the are completly equal)
	return $b;
	}

}