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)

(*
ocamlfind ocamlopt -package batteries -linkpkg main.ml -o a.out
*)
open Batteries

let lst = Str.split (Str.regexp "") (read_line ())
          |> List.sort compare
let lst2 = List.sort_uniq compare lst
let lst3 = 
        List.map (fun elmnt1 ->
                List.filter (fun elmnt2 ->
                        elmnt1 = elmnt2
                ) lst
        ) lst2
let lst4 = List.map (fun elst ->
        List.length elst
) lst3

let () =
        (
                if List.exists (fun elmnt -> elmnt mod 2 = 1) lst4 then
                        "No"
                else
                        "Yes"
        ) |> Printf.printf "%s\n"