sub beautify {
   %old = %new;
   sort { $a <=> $b }
   grep { $new{$_}++;
          $old{$_}++ unless exists $old{$_};
          ($new{$_}   == $old{$_}) ? 1 :
          ($new{$_}-1 == $old{$_}) ? 1 : 0;
        } @_;
}