import Control.Applicative ((<$>))
import Control.Monad (replicateM)

import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

import Data.List

import Data.Char (isSpace)

main :: IO ()
main = do
  solve <$> replicateM 3 (getl $ readil B.readInt) >>= print

solve :: [[Int]] -> Int
solve [[aw, ab], [bw, bb], [c, d]] =
  let abw = c - (min c ab)
      baw = min d (bw + abw)
  in aw - abw + baw

getl :: (ByteString -> a) -> IO a
getl f = f <$> B.getLine

readil :: Integral a =>  (ByteString -> Maybe (a, ByteString)) -> ByteString -> [a]
readil f = unfoldr g
  where
    g s = do
      (n, s') <- f s
      return (n, B.dropWhile isSpace s')