I understand you are just starting out. I have been following your posts as of recent days. Somewhere prior to the use of $in{$_}, you must declare %in with my %in.

I must ask that you read some material prior to your continuation in perl. Check out perldata for information regarding variables and symbols in perl. Check out perlfunc and perlop for information on the various methods and operators available within the language. Be certain to read perlref, perllol and perldsc for more information regarding complex data structures and how they work.

Hope this helps.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1