import Control.Applicative ((<$>))

getRemainder :: [Int] -> [Int]
getRemainder cs@(b0 : _) = if bs == [] then [0] else bs
    where
        fp1 = sum cs
        fm1 = sum $ zipWith (*) cs $ cycle [1, -1]
        b2 = subtract b0 $ flip div 2 $ fp1 + fm1
        b1 = flip div 2 $ fp1 - fm1
        bs = reverse $ dropWhile (== 0) [b2, b1, b0]

main :: IO ()
main = do
    _ <- getLine
    bs <- getRemainder . map read . words <$> getLine
    print $ subtract 1 $ length bs
    putStrLn $ unwords $ map show bs