my @sorted =
        map{$_->[0]}
        sort {$a->[1] <=> $b->[1]}
        map{
         /chr(\w+)/;
         my $x = $1;
         if ($x eq "X") {$x=23}
         if ($x eq "Y") {$x=24}
         $_=[$_,$x]
        } @unsorted;