(defun bitto10 (bit)
    (cond ((equal bit '0) 0)
          ((equal bit '1) 1)
          (t (+ (mod bit 10) (* 2 (bitto10 (/ (- bit (mod bit 10)) 10)))))))

(defun solve (a b) (bitto10 (logxor a b)))
(princ (solve (read) (read)))