(defun is-perfect-number (n)
  (if (< n 2)
      nil
      (let ((sum 1)
            (sqrt-n (isqrt n)))
        (loop for i from 2 to sqrt-n do
          (when (zerop (mod n i))
            (incf sum i)
            (let ((other (/ n i)))
              (unless (= i other)
                (incf sum other)))))
        (= sum n))))

(defun main ()
  (let ((n (read)))
    (if (is-perfect-number n)
        (format t "Yes~%")
        (format t "No~%"))))

(main)