readArray::IO String -> IO[Int]
readArray = fmap $ map read . words
res a b c d
    |abs (c-a) <= d = "Yes"
    |abs (b-a) <= d && abs (c-b) <= d = "Yes"
    |otherwise = "No"
main = do
    [a,b,c,d] <- readArray getLine
    putStrLn $ res a b c d