import qualified Data.ByteString.Char8 as C
import Data.Maybe ( fromJust )

readInts :: IO [Int]
readInts = map (fst . fromJust . C.readInt) . C.words <$> C.getLine

main :: IO ()
main = do
  [a,b] <- readInts
  print $ (a+b+1) `div` 2