Can Form Palindrome

Given a string s consisting only of lowercase English letters, determine whether its characters can be rearranged to form a palindrome.

A palindrome is a string that reads the same forwards and backwards. One necessary and sufficient condition for a string to be rearranged into a palindrome is that at most one character appears an odd number of times. Formally, if the frequency of each character is given by \( f(c) \), then the string can form a palindrome if and only if:

\[ \sum_{c \in s} [f(c) \bmod 2 \neq 0] \leq 1 \]

Write a program that reads the string from standard input and prints YES if it can be rearranged into a palindrome, and NO otherwise.

inputFormat

The input consists of a single line containing a string s (1 ≤ |s| ≤ 10⁶), which is composed of lowercase English letters only.

outputFormat

Output a single line containing either YES or NO depending on whether the given string can be rearranged into a palindrome.

## sample

aaabbbb

YES