let a, b, c = Scanf.scanf "%d %d %d\n" (fun a b c -> a, b, c)
module IntSet =
  Set.Make (struct
    type t = int
    let compare i j = i - j
  end)

open IntSet

let set = add a (add b (add c empty))

let () = print_int @@ List.length (elements set);
  print_newline ()
