public static function plainNumber(string $value) : int {
		$temp = explode('ext', $value);
		$result = preg_replace('/[^0-9]/', '', $temp[0]);
		// remove first 1 in US numbers
		if (strlen($result) == 11 && $result[0] == 1) {
			$result = substr($result, 1);
		}
		return $result;
	}