Parse text file with regex

#!/usr/bin/perl -n

use feature qw(say);
use English;

BEGIN {
    my %h;
}

if (/(\w\w_map) (\d)/) {
    $map_action = $1;
    $num = $2;
    $h{$key}->{$map_action} = $num;
}
else {
    chomp;
    $key = $_;
    $h{$key} = {};
}

END {
    for $m (keys(%h)) {
        print "${m}:" . $RS;
        for $n (keys(%{$h{$m}})) {
            print "\t${n} " . $h{$m}->{$n} . $RS;
        }
    }
}