sub gcd {
	my ($a, $b, $c);
	($a, $b) = @_;
	if ($a == 0) {
		$c = $a;
	} else {
		my (@a, @b);
		my $n;
		$a[0] = $a;
		$b[0] = $b;
		$n = 0;
		while(1) {
			if ($b[$n] == 0) {
				$c = $a[$n];
				last;
			}
			$a[$n+1] = $b[$n];
			$b[$n+1] = $a[$n] % $b[$n];
			$n++;
		}
	}
	return $c;
}

print gcd(99, 22);