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 = 0;

            for(var i = 0; i < length; i++){
                for(var j = i + 1; j < length; j++){
                    var tmp = new char[length];
                    n.CopyTo(tmp, 0);
                    var t = tmp[i];
                    tmp[i] = tmp[j];
                    tmp[j] = t;

                    string str = tmp.Aggregate(string.Empty, (current, c) => current + c);
                    max = Math.Max(max, int.Parse(str));
                }
            }

            Console.WriteLine(max);
        }
    }
}