module Mochi = Set.Make(Int32)

let main () =
  let n = Scanf.scanf "%d\n" Batteries.identity in
  let xs = Array.make n 0 in
  for i = 0 to n - 1 do
    xs.(i) <- Scanf.scanf "%d\n" Batteries.identity;
  done;
  let mochi = Array.fold_left (fun acc elm -> Mochi.add (Int32.of_int elm) acc) Mochi.empty xs in
  Printf.printf "%d\n" @@ BatList.length (Mochi.elements mochi)

let _ = main ()
