open Batteries

let input_ints () =
  let input = IO.read_line IO.stdin in
   String.split_on_char ' ' input
   |> List.map int_of_string

let last l =
   (-) (List.length l) 1
   |> List.nth l

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

let _ = main ()

