let main () =
  let a, b, c, d = Scanf.scanf "%d %d %d %d" (fun a b c d -> (a,b,c,d)) in
  if (abs @@ (-) b a <= d && abs @@ (-) c b <= d) || abs @@ (-) a c <= d  then
    print_string "Yes\n"
  else
    print_string "No\n"

let _ = main ()
