import Control.Monad
import Control.Applicative
import Data.List
import Data.Ord
import Data.List.Split

input = getLine :: IO String
ii = readLn :: IO Int
li = map read . words <$> getLine :: IO [Int]

pairwise :: [a] -> [(a, a)]
pairwise xs = zip xs (drop 1 xs)

fold :: (b -> a -> b) -> b -> [a] -> b
fold = foldl'

main :: IO ()
main = do
  putStrLn "Hello World!"