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)

(* O(n) *)
let w = read_line ()
let n = String.length w
let _ =
  for i = Char.code 'a' to Char.code 'z' do
    let c = ref 0 in
    String.iter (fun x -> if x = Char.chr i then incr c) w;
    if !c mod 2 <> 0 then (print_endline "No"; exit 0)
  done;
  print_endline "Yes"