object Main {

  def calc(a: Int, b: Int, c: Int, d: Int): Boolean = {
    math.abs(a - b) <= d && math.abs(b - c) <= d
  }

  def main(args: Array[String]): Unit = {
    val in = io.Source.fromInputStream(System.in).getLines()
    val Array(a, b, c, d) = in.next().split(' ') map (_.toInt)
    System.out.println(if (calc(a, b, c, d)) "Yes" else "No")
  }
}