#!/usr/bin/perl
use v5.35.0;

my $matches = 0;
my $towels;
while (<>) {
	chomp;
	next if /^$/;
	if (defined $towels) {
		$matches += /$towels/o;
	} else {
		$towels = '^(?:' . s/, /|/gr . ')+$';
	}
}
say $matches;