Palindrome Permutation Check

Given a string, determine whether any permutation of the string can form a palindrome. A palindrome reads the same forwards and backwards. The key observation is that in a palindrome, at most one character can appear an odd number of times. Mathematically, if we denote the frequency of a character c in the string by \(f(c)\), then a permutation of the string can form a palindrome if and only if:

$$\sum_{c \in S}{[f(c) \mod 2 = 1]} \le 1.$$

Your task is to read the input string from standard input and print YES if a palindrome permutation exists and NO otherwise.

inputFormat

The input is a single line containing a non-empty string s consisting of lowercase English letters.

Input Format:

s

outputFormat

Print a single line with YES if any permutation of the string can form a palindrome, or NO otherwise.

civic

YES