{-# LANGUAGE OverloadedStrings #-}
import Data.Char
import Data.List
import Control.Monad
import qualified Data.ByteString.Char8 as BS

main :: IO ()
main = do
  n <- head.parseLine <$> BS.getLine
  BS.putStrLn . BS.pack . show $ if even n then (n`div`2) else (n`div`2+1)
  where
     parseLine = unfoldr (BS.readInt . BS.dropWhile isSpace)