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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.chars().distinct().filter(i -> i-48 != 0).count() < 2) {
            System.out.println("-1");
            return;
        }

        char[] chars = s.toCharArray();
        Arrays.sort(chars);

        StringBuilder sb = new StringBuilder();
        for (int i=0;i<chars.length - 2;i++) {
            sb.append(chars[chars.length - i - 1]);
        }
        sb.append(chars[0]);
        sb.append(chars[1]);

        System.out.println(sb.toString());
    }
}