let () =
  let a, b, c = Scanf.scanf "%d %d %d " (fun a b c -> a, b, c) in
  let a, b, c = float a, float b, float c in
  print_endline (if (a /. b |> ceil) *. 2. /. 3. >= (a /. c |> ceil) then "YES" else "NO")