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

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Console.ReadLine().Select(c => c == '0' ? 10 : (c - '0')).Sum();
            Console.WriteLine(n);
        }
    }
}