using System;
using System.Linq;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var line1 = Console.ReadLine();

            var s = line1;
            int result = 0;

            foreach(var c in s)
            {
                if (int.TryParse(c.ToString(),out int index))
                {
                    result = result + index;
                }
            }

            //結果を表示
            Console.WriteLine(result);
        }
    }
}