(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((d (read))
         (a (make-array (1+ d) :element-type 'integer))
         (b 0))
    (dotimes (i (1+ d)) (setf (aref a i) (read)))
    (loop for i from (- d 3) downto 0 do
          (setf (aref a (1+ i)) (+ (aref a (1+ i)) (aref a (+ i 3)))
                (aref a (+ 3 i)) 0))
    (dotimes (i (1+ d))
      (unless (zerop (aref a i))
              (setq b i)))
    (format t "~d~%" b)
    (dotimes (i (1+ b))
      (if (= i b)
          (format t "~d~%" (aref a i))
          (format t "~d " (aref a i))))))

(main)