use warnings;
use strict;

my %hoh = (
 kevin => {
   age   => "12",
   favorite_color       => "blue",
   gender       => "boy",
 },
 john => {
   age   => "11",
   favorite_color       => "green",
   gender       => "boy",
 },
 lisa => {
   age   => "11",
   favorite_color       => "pink",
   gender       => "girl",
 },
 sara => {
   age   => "13",
   favorite_color       => "purple",
   gender       => "girl",
 },
 shelly => {
   age   => "12",
   favorite_color       => "purple",
   gender       => "girl",
 },
);

my $num_12 = grep { $_ == 12 } map { $hoh{$_}->{'age'} } keys %hoh;

my $num_alt = grep { $hoh{$_}->{'age'} == 12 } keys %hoh;

print "Num 12: $num_12\n";
print "Num 12 alt: $num_alt\n";
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