main :: IO()
main = do
    [a,b,c,d] <- map read . words <$> getLine
    putStrLn $ if (abs(a,c) <= d || abs(a,b) <= d && abs(b,c) <= d) then "Yes" else "No"
    
abs :: Int -> Int -> Int
abs num1 num2
    | num1 > num2		= num1 - num2
    | otherwise			= num2 - num1