using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Yuki
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            var a =  new List<int>();
            foreach (var item in s) a.Add(int.Parse(item.ToString()));
            a.Sort();
            a.Reverse();
            s = "";
            foreach (var item in a) s += item;
            Console.WriteLine(s);
        }
    }
}