let arr_of_str s = Array.init (String.length s) (fun i -> s.[i])
let f b c = b lxor (1 lsl (int_of_char c - 97))
let () =
  let st = Scanf.scanf "%s" arr_of_str |> Array.fold_left f 0 in
  print_endline (if st = 0 then "Yes" else "No")
