In addition to what's been said above, I'd like to throw some more links at you that may be useful in this and future scenarios:

• perlop: The Arrow Operator
• perldsc - Perl Data Structures Cookbook (introduction to/tutorial for nested data structures)
• Data::Dumper - useful for debugging, to find out what structure your data has. For instance, in your case, you could do this:
  
  

  use feature qw/say/;
  use Data::Dumper;
  
  # ...
  
  say Dumper \%hash;
  [download]

  
  ...and you'd immediately get a pretty good idea of what kinda structure %hash actually contains.

Hope these help!