using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {
            var S = Console.ReadLine();
            int sum = 0;
            foreach (char ss in S)
            {
                if (char.IsDigit(ss))
                {
                    sum += int.Parse(ss.ToString());
                }
            }
            Console.WriteLine(sum);
        }
    }
}