import scala.io.StdIn

object Main extends App {
  val Array(a, b, c, d) = StdIn.readLine().split(' ').map(_.toInt)

  val ac = scala.math.abs(a - c)
  val ab = scala.math.abs(a - b)
  val bc = scala.math.abs(b - c)

  println(if (ac <= d || (ab <= d && bc <= d)) "Yes" else "No")

}
