import Control.Monad

readInts :: String -> [Int]
readInts = map read . words

getInts :: IO [Int]           
getInts = liftM readInts getLine

main = do
  [x, y] <- getInts
  [x2, y2] <- getInts
  print $ if x == y && x2 == y2 && x2 < x
          then x + 1
          else x + y - min x y