use prime;
use strict;

our @prime = prime::make_prime_table(100 * 10000);

my $prime_count = 0;
my $prime_rate = 1.0;
my $n;
my $side_count = 5;

for ($n = 3; ; $n += 2, $side_count += 4) {
	$prime_count += count_prime(get_4side($n));
	$prime_rate = $prime_count / $side_count;
	
	if ($prime_rate < 0.1) {
		print "$n, $prime_rate\n";
		exit(0);
	}
}

sub count_prime
{
	my @sidenums = @_;
	my $count = 0;
	
	foreach my $p (@sidenums) {
		if (prime::is_prime($p, \@prime)) {
			++$count;
		}
	}
	
	return $count;
}

sub get_4side
{
	my $n = shift;
	
	my $rb = $n * $n;
	my $lb = $rb - ($n - 1);
	my $lt = $lb - ($n - 1);
	my $rt = $lt - ($n - 1);
	
	return ($rb, $lb, $lt, $rt);
}