using System;
using System.Linq;

namespace No39_1{
    public class Program{
        public static void Main(string[] args){
            var n = Console.ReadLine().ToCharArray();
            var length = n.Length;
            var max = n.Max();
            var index = 0;

            foreach(var c in n){
                if(c == max){
                    index++;
                } else{
                    break;
                }
            }

            var tmp = n[index];
            for(var i = length - 1; i > index; i--){
                if(n[i] == max){
                    n[index] = n[i];
                    n[i] = tmp;
                    break;
                }
            }

            Console.WriteLine(n);
        }
    }
}