using System;

namespace prob289
{
    class Program
    {
        static void Main(string[] args)
        {
            char[] a = Console.ReadLine().ToCharArray();
            int r = 0;
            int b = 0; ;
            foreach (var i in a)
            {
                if (int.TryParse(i.ToString(),out b))
                {
                    r += b;
                }
            }
            Console.WriteLine(r);
        }
    }
}