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

namespace y
{
    class Program
    {
        static void Main(string[] args)
        {
            var a = Console.ReadLine();
            int ans = 0;
            foreach (var item in a)
            {
                if (item == '0')
                {
                    ans += 10;
                }
                else
                {
                    ans += int.Parse(item.ToString());
                }
            }

                Console.WriteLine(ans);
        }
    }
}