(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((a (read))
         (b (read))
         (res (if (= a b) 2 1)))
    (loop while (not (zerop (+ a b)))
          when (not (zerop (logand (+ a b) 1)))
            do (setf res (* res (* 2 (logand b 1))))
          do (setf a (ash a -1)
                   b (ash b -1)))
    (format t "~d~%" (floor res 2))))

(main)