using System;
using System.Collections.Generic;
namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
#if LocalDebug
            var exStdIn = new System.IO.StreamReader("stdin.txt");
            System.Console.SetIn(exStdIn);
#endif
            var Input = Console.ReadLine();
            var Sum = 0;

            for (int i = 0; i < Input.Length; i++)
            {
                if (('1' <= Input[i]) && (Input[i] <= '9'))
                {
                    Sum += (Input[i] - '0');
                }
            }
            Console.WriteLine(Sum);


#if LocalDebug
            System.Console.ReadKey();
#endif
        }


        static int GetData()
        {
            return int.Parse(Console.ReadLine());
        }

        static string[] GetList()
        {
            return Console.ReadLine().Split(' ');
        }



    }
}