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