(|>) :: a -> (a -> b) -> b
infixl 1 |>
x |> f = f x

($>) :: (Functor m) => m a -> (a -> b) -> m b
infixl 1 $>
x $> f = fmap f x

getNums = getLine $> words $> map read

main = do
  list <- getNums :: IO [Float]
  list |> sum |> (/ 2) |> ceiling |> print