import Control.Monad
import Text.Printf
import Control.Applicative

main :: IO()
main = do
  [a, b, c, d] <- map read . words <$> getLine
  let abDist = abs (a - b)
      bcDist = abs (b - c)
      acDist = abs (a - c) 
  printf "%s" $ if d >= minimum [acDist, maximum [bcDist, abDist]] then "Yes" else "No"
