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)

merge xs [] = xs
merge [] xs = xs
merge (x:xs) (y:ys)
  | x < y     = x : merge xs (y:ys)
  | otherwise = y : merge (x:xs) ys

msort [] = []
msort [x] = [x]
msort xs = merge (msort $ take h xs) (msort $ drop h xs)
  where h = length xs `div` 2

judge [] = True
judge (x:xs)
  | even $ length $ filter (== x) (x:xs)  = judge xs'
  | otherwise                             = False
  where xs' = snd $ break (/= x) (x:xs)


main = do
  ans <- judge . msort <$> getLine
  putStrLn (if ans then "Yes" else "No")