http://golf.shinh.org/p.rb?Crazy+operation+in+Malbolge+EASY

crz.lisp

(defun parse (str)
  (loop for i from 0 below (length str)
        if (eq (aref str i) #\Space)
        return (values (subseq str 0 i)
                     (subseq str (1+ i)))))

(defun crz (x y)
  (case x
    (#\0 (case y
         (#\0 #\1)
         ((#\1 #\2) #\0)))
    (#\1 (case y
         (#\0 #\1)
         (#\1 #\0)
         (#\2 #\2)))
    (#\2 (case y
         ((#\0 #\1) #\2)
         (#\2 #\1)))))

(defun call-crz (str)
  (multiple-value-bind (x y) (parse str)
    (map 'vector #'crz x y)))

(loop for l = (read-line)
      while l
      do (format t "~a~%" (coerce (call-crz l) 'string)))