//https://www.hackerrank.com/contests/ieeextreme-challenges/challenges/game-of-thrones/submissions/code/4149531

import java.io.*;

import java.util.*;

import java.text.*;

import java.math.*;

import java.util.regex.*;

public class Solution {

private static boolean isPalindrom(String input) {

int array[] = new int[255];

for (int i = 0; i < 255; i++)

array[i] = 0;

for(int i = 0; i < input.length() ; i++){

array[input.charAt(i)] +=1;

}

int odd = 0;

for (int i = 0; i < 255; i++) {

if (array[i] % 2 == 1) odd +=1;

}

if (odd <= 1) return true;

return false;

}

public static void main(String[] args) {

Scanner myScan = new Scanner(System.in);

String inputString = myScan.nextLine();

System.out.println(isPalindrom(inputString) ? "YES" : "NO");

// String ans;

// Assign ans a value of YES or NO, depending on whether or not inputString satisfies the required condition

// System.out.println(ans);

myScan.close();

}

}