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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import qualified Data.Set as S
 
main = putStr =<< f S.empty <$> getLine
 
f s []
  | S.null s = "Yes"
  | otherwise = "No"
f s (x:xs)
  | S.member x s = f (S.delete x s) xs
  | otherwise = f (S.insert x s) xs