import junit.framework.TestCase;

import java.util.Arrays;
import java.util.Scanner;

public class BeautifulString20171224Test extends TestCase {

    public static void main(String[] args) {
        //  System.out.println("enter a string");
        Scanner scan = new Scanner(System.in);
        String str1 = scan.next();
        if (str1.length() < 100000) {
            String str2 = makeBeautiful(str1);
            if (str2 != null) {
                System.out.println("YES");
                System.out.println(str2);
            } else
                System.out.println("NO");
        }

    }

    private static String makeBeautiful(String original) {
        if (original.length() % 2 != 0) {
            return null;    // Strings of odd length always "fail" on the middle character.
        }

        if (isBeautiful(original)) {
            return reverse(original);   // Is already "beautiful."
        }

        final String sorted = sortChars(original);
        final int indexRightOfCenter = original.length() / 2;
        if (sorted.charAt(0) == sorted.charAt(indexRightOfCenter) || sorted.charAt(indexRightOfCenter - 1) == sorted.charAt(sorted.length() - 1)) {
            return null;    // One character fills more than half of the array.
        }

        final CharSequence leftHalf = sorted.subSequence(0, indexRightOfCenter);
        final CharSequence rightHalf = sorted.subSequence(indexRightOfCenter, sorted.length());
        return leftHalf + reverse(rightHalf);
    }

    private static boolean isBeautiful(final String value) {
        if (value.length() == 0) {
            return true;
        }
        final int centerIndex = value.length() / 2;
        for (int charIdx = 0; charIdx <= centerIndex; ++charIdx) {
            if (value.charAt(charIdx) == value.charAt(value.length() - charIdx - 1)) {
                return false;   // Found duplicate character.
            }
        }
        return true;    // No duplicates found.
    }

    private static String reverse(final CharSequence value) {
        return new StringBuilder(value).reverse().toString();
    }

    private static String sortChars(final String original) {
        final char[] characters = original.toCharArray();
        Arrays.sort(characters);
        return new String(characters);
    }

    public void testMultipleValues() {
        assertIsBeautiful("");
        isNotBeautifiable("a");
        isNotBeautifiable("aa");
        assertIsBeautiful("ab");
        isNotBeautifiable("abc");
        assertIsBeautiful("aabb");
        isBeautifiable("abba");
        isBeautifiable("abbc");
        isNotBeautifiable("abaa");
        isNotBeautifiable("abcde");
        assertIsBeautiful("aaabbb");
        isNotBeautifiable("abaaab");
        isBeautifiable("abccba");
        isBeautifiable("aabbba");
        isNotBeautifiable("abcdefghijklmnopqrstuvwxyza");
        isBeautifiable(copies(80, "abcdefghijklmnopqrstuvwxyz") + "aa");
        isBeautifiable(copies(3846, "abcdefghijklmnopqrstuvwxyz") + "aa");
        isBeautifiable(copies(4000, "abcdefghijklmnopqrstuvwxyz") + "aa");
        isNotBeautifiable("abbb");
        isNotBeautifiable("aabbbb");
    }

    private String copies(final int numberOfCopies, final String value) {
        final StringBuilder stringBuilder = new StringBuilder();
        for (int counter = 0; counter < numberOfCopies; ++counter) {
            stringBuilder.append(value);
        }
        return stringBuilder.toString();
    }

    private static void assertIsBeautiful(final String beautifulStringValue) {
        assertEquals("The String value <" + beautifulStringValue + "> is beautiful;", true, isBeautiful(beautifulStringValue));
        assertEquals("The String value <" + beautifulStringValue + "> is beautiful;", reverse(beautifulStringValue), makeBeautiful(beautifulStringValue));
    }

    private static void isNotBeautifiable(final String original) {
        assertEquals("The String value <" + original + "> is NOT beautiful;", false, isBeautiful(original));
        assertEquals("The String value <" + original + "> is NOT beautiful;", null, makeBeautiful(original));
    }

    private static void isBeautifiable(final String original) {
        assertEquals("The String value <" + original + "> is NOT beautiful;", false, isBeautiful(original));

        final String butified = makeBeautiful(original);
        if (butified == null) {
            fail("The String value <" + original + "> is should be beautifyable.");
        } else {
            assertEquals("The String value <" + original + "> is should be beautifyable, as value <" + butified + ">;",
                    true, isBeautiful(butified));
            assertEquals("The String value <" + original + "> and butified value <" + butified + "> should be the same length;",
                    original.length(), butified.length());
            assertEquals("The String value <" + original + "> and butified value <" + butified + "> should be the same length;",
                    sortChars(original), sortChars(butified));
        }
    }

}