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 Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(defun outer (l1 l2)
 (union (set-difference l1 l2)
        (set-difference l2 l1)))

(defun solve (l tl)
  (cond 
    ((null l) (if (null tl) "Yes" "No"))
    (t (solve (cdr l) (outer tl (list (car l)))))))

(defun main ()
  (let ((str (read-line)))
    (princ (solve (loop :as c 
                        :across str 
                        :collect c) 
                  '()))))

(main)