AoC 2021 day 3, part 1 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

use List::AllUtils qw(pairwise);

my @counts = (0) x 12;
while (<>) {
    chomp;
    @counts = pairwise {$a + $b} @counts, @{[split //]};
}

my $half = $. / 2;
my $gamma = oct("0b" . join( '', map {int($_ > $half)} @counts ));

print "Part 1: ", $gamma * ($gamma ^ 0xFFF), "\n";