open Batteries

let input_ints ()  =
  read_line()
  |> String.split_on_char ' '
  |> List.map int_of_string

let main ()=
  let l = input_ints () in
  let a = List.nth l 0 in
  let b = List.nth l 1 in
  let c = List.nth l 2 in
  let d = List.nth l 3 in
  if abs(a-b) <= d && abs(b-c) <= d then
    print_string "Yes\n"
  else
    print_string "No\n"

let () = main ()
