use strict;
use warnings;
use diagnostics;

my @f = <DATA>;
foreach my $line (@f) {
  my @AB = split("\t", $line);
  my @AA = sort { $a->[1] <=> $b->[1] } @AB;
  foreach my $temp (@AA) {
    print "@$temp\t", "\n";
  }
}

__DATA__
AA 34
AB 22
AC 12