main = do
  d <- readLn
  bs <- map read . words <$> getLine
  let r = poly d (reverse bs)
  let n = length r - 1
  print n
  putStrLn $ unwords (map show r)

poly d bs
  | all (== 0) bs = [0]
  | d == 3 && bs!!0 == bs!!2 && bs!!1 == 0 = [0]
  | d < 3 = reverse (dropWhile (== 0) bs)
  | head bs == 0 = poly (d - 1) (tail bs)
  | otherwise = let (b1:b2:b3:br) = bs in poly (d - 1) (b2:(b3+b1):br)