(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((s (read-line))
         (n (length s)))
    (dotimes (i n)
      (if (evenp i)
          (when (char= #\space (char s i))
                (format t "No~%")
                (return-from main))
          (when (char/= #\space (char s i))
                (format t "No~%")
                (return-from main))))
    (format t "Yes~%")))

(main)