module Main where
 
main :: IO ()
main = do
  _ <- getLine
  a <- getIntList
  mapM_ putStrLn $ solve a
 
m :: [Int]
m = [1, 0, -1, 0] ++ [0, 0 ..]
 
solve :: [Int] -> [String]
solve a = fmt . loop $ reverse a
  where
  loop a' | length a' <= 4 = calc a'
          | otherwise      = loop $ calc a'
 
fmt :: [Int] -> [String]
fmt ns | s2 == []  = ["0", "0"]
       | otherwise = [s1] ++ [s2]
  where
  s1 = show . pred $ length s2
  s2 = unwords . reverse . map show $ dropWhile (==0) ns
 
calc :: [Int] -> [Int]
calc ns = tail $ zipWith (-) ns $ map (* (head ns)) m
 
getIntList :: IO [Int]
getIntList = map read . words <$> getLine

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8
0 -5 0 4 0 1 -1 0 1