using static System.Console;
namespace App
{
    class Prog
    {
        static void Main()
        {
            var x = ReadLine();
            int c = 0;
            for (int i = 0; i < x.Length; i++)
            {
                if(x.Substring(i, 1) == "0")
                {
                    c += 10;
                }
                else
                {
                    c += int.Parse(x.Substring(i, 1));
                }
            }
            WriteLine(c);
        }
    }
}