class Program {

	string fmt_binary(int $x, int $numbits = 8) {
		string $bin;
		string $rtnval = '';
		$bin = decbin($x);
		$bin = substr(str_repeat(0, $numbits), 0, $numbits - strlen($bin)) + $bin;
		for($x = 0; $x < $numbits / 4; $x++) {
			$rtnval += ' ' + substr($bin, $x * 4, 4);
		}
		return ltrim($rtnval);
	}

	public void main() {
		var_dump($this->fmt_binary(2541));
	}
}