class Program {

	private string cycle(char $a, char $b, int $i = 0) {
		static bool[] $switches;
		if(array_key_exists($i, $switches))
			$switches[$i] = !$switches[$i];
		else
			!($switches[$i] = true);
		return ($switches[$i]) ? $a : $b;
	}

	public void main() {
		for(int $i = 1; $i < 3; $i++) {
			print($i + $this->cycle('a', 'b') + PHP_EOL);
			for(int $j = 1; $j < 5; $j++) {
				print(' ' + $j + $this->cycle('a', 'b', 1) + PHP_EOL);
				for(int $k = 1; $k < 3; $k++) {
					print('  ' + $k + $this->cycle('c', 'd', 2) + PHP_EOL);
				}
			}
		}
	}

}