let () =
  let n = Scanf.scanf "%d\n" (fun x -> x) in
  let list_of_string str =
    let l = String.length str in
    let rec iter i lst =
      if i >= l then lst
      else iter (i+1) ((int_of_char str.[i] - 48) :: lst) in
    iter 0 [] in
  let slst = list_of_string (string_of_int n) in
  let n = if List.for_all (fun n -> n = 1 || n = 3) slst
    then List.fold_left (fun a b -> if b = 3 then a + 1 else a) 0 slst
    else -1 in
  Printf.printf "%d\n" n