open Printf
open Scanf

module SI = Set.Make(
                struct
                  type t = int
                  let compare = compare
                end
              )
                    
let () =
  let n = scanf "%d " (fun x -> x) in
  let rec loop i st =
    if i = 0 then SI.cardinal st
    else
      let a = scanf "%d " (fun x -> x) in
      if SI.mem a st then loop (i-1) (SI.remove a st)
      else loop (i-1) (SI.add a st) in
  loop n SI.empty |> printf "%d\n"
