$ perl -e 'my $m = 20; print $m++ + $m++, "\n"'
41

$ perl -e 'my $m = 20; print $m++ + ++$m, "\n"'
42

$ perl -e 'my $m = 20; print ++$m + $m++, "\n"'
43

$ perl -e 'my $m = 20; print ++$m + ++$m, "\n"'
44

##</code><code>##

s**lil*;  $*=join'',sort split q**;  s;.*;grr; &&s+(.(.)).+$2$1+; $; =
qq-$_-;s,.*,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$*,$/)