using System;
using System.Linq;
using System.Collections.Generic;

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var X = Console.ReadLine();
            var ans = X.OrderByDescending(z => z).ToArray();
            var bef = new string(ans);

            Swap(ref ans[ans.Length - 1], ref ans[ans.Length - 2]);

            var last = new string(ans);

            if (last[0] == '0' || bef == last)
                Console.WriteLine(-1);
            else
                Console.WriteLine(last);
        }

        public static void Swap<T>(ref T one, ref T two)
        {
            var temp = one;
            one = two;
            two = temp;
        }
    }
}