Problem:
Score : 200 points

Problem Statement

Let w be a string consisting of lowercase letters.
We will call w beautiful if the following condition is satisfied:

Each lowercase letter of the English alphabet occurs even number of times in w.

You are given the string w. Determine if w is beautiful.

Constraints

1 \leq |w| \leq 100

w consists of lowercase letters (a-z).

Input

The input is given from Standard Input in the following format:

w

Output

Print Yes if w is beautiful. Print No otherwise.

Sample Input 1

abaccaba

Sample Output 1

Yes

a occurs four times, b occurs twice, c occurs twice and the other letters occur zero times.

Sample Input 2

hthth

Sample Output 2

No

Solution in OCaml (4.02.3) (judge verdict: Accepted)

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")