import Data.Bool

main :: IO ()
main = do
  [a, b, c, d] <- map read . words <$> getLine
  putStr $ bool "No" "Yes" $ solve a b c d

solve :: Int -> Int -> Int -> Int -> Int
solve a b c d
  | abs (a - c) <= d = True
  | abs (a - b) <= d && abs (b - c) <= d = True
  | otherwise = False
