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 w = read_line ()
let f s x = let n = ref 0 in String.iter (fun c -> if c = x then incr n) s; !n
let _ = String.iter (fun c -> if f w c mod 2 = 1 then (print_endline "No"; exit 0)) w; print_endline "Yes"