use strict;
use warnings;

(my $datastring=do{local $/=undef; <DATA>}) =~s/:/=>/g;
my $data = eval $datastring;

my %by_name = map { $_->{name} => $_->{id} } @{$data->{'genres'}};
print "The ID for Science Fiction is:", $by_name{"Science Fiction"} , "\n";
__DATA__
<<<YOUR JSON Here...>