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

static class NagataKanaIsAGenius {
    public static void Main() {
        char[]s=Console.ReadLine().ToArray();
        if(s.Length==2&&s[1]=='0'){
            Console.WriteLine(-1);
            Environment.Exit(0);
        }
        Array.Sort(s);
        Array.Reverse(s);
        s[s.Length-2]^=s[s.Length-1];
        s[s.Length-1]^=s[s.Length-2];
        s[s.Length-2]^=s[s.Length-1];
        foreach(char c in s){
            Console.Write(c);
        }
        Console.WriteLine("");
    }
}