foreach my $key1 (sort keys %somehash) {
   foreach my $key2 (sort keys %{$somehash{$key1}}) {
      foreach my $key3 (sort keys %{$somehash{$key1}{$key2}}) {
         print($key1, ':', $somehash{$key1}{$key2}{$key3}, "\n");
      }
   }
}