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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            char[] cs = Console.ReadLine().ToCharArray();
            List<int> listn = new List<int>();
            int s;
            int a = 0;
            int count = 0;
            for (int i = 0; i < cs.Length; i++)
            {
                if (int.TryParse(cs[i].ToString(), out s))
                {
                    listn.Add(int.Parse(cs[i].ToString()));
                }
            }
            for (int i = 0; i < listn.Count; i++)
            {
                count = count + listn[i];
            }
            Console.WriteLine(count);
        }
    }
}