let () =
    let n = Scanf.scanf "%d\n" (fun x -> x) in 
    let lst = Array.to_list (Array.init n (fun _ -> Scanf.scanf "%d " (fun x -> x))) in 
    let s = List.fold_left (fun a b -> if List.length (List.filter (fun x -> b = x) lst) = 1 then a + 1 else a) 0 lst in
    Printf.printf "%d\n" s