(defun toggle-last-bit (s)
  (if (string= (subseq s (1- (length s))) "0")
      (concatenate 'string (subseq s 0 (1- (length s))) "1")
      (concatenate 'string (subseq s 0 (1- (length s))) "0")))

(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((s (read-line)))
    (format t "~a~%" (toggle-last-bit s))))

(main)