A String is called Palindrome if it reads the same backwards as well as forwards. For example, the String aba can be read the same backwards as well as forwards.
Now, a Permutation of a String S is some String K where S and K contain the same set of characters, however, these characters need not necessarily have the same positions. For Example, consider the String abc. Here, the Strings :
acb
bca
bac
cab
cba

are all permutations of it.

Now, given a String S consisting of lowercase English alphabets, you need to find out whether any permutation of this given String is a Palindrome. If yes, print "YES" (Without quotes) else, print "NO" without quotes.

Input Format:
The first and only line of input contains the String S.

Output Format:
Print the required answer on a single line

Constraints:
1 ≤ |S| ≤ 1000
S[i] ∈ [a,z]

SAMPLE INPUT
abab

SAMPLE OUTPUT
YES

Explanation

Here, the permutation abba is a palindrome.

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