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

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var s0 = Console.ReadLine();
            var s1 = s0.OrderByDescending(c => c).ToArray();
            Console.WriteLine(s1);
            Console.ReadLine();
        }
    }
}