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

	if(math.abs(a-b) <= d && math.abs(b-c) <= d){
		println("Yes")
	}else if(math.abs(a-c) <= d){
		println("Yes")
	}else{
		println("No")
	}
	
}