Or do you need:

sub RowSort {

  my ($a1, $a2) = $a =~ /(\d+)\,(\d+)/;
  my ($b2, $b2) = $b =~ /(\d+)\,(\d+)/;

  my $am = $a1.$a2;
  my $bm = $b1.$b2;

  $am <=> $bm;
}
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