using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Yuki
{
    class Program
    {
        static void Main(string[] args)
        {
            string S = Console.ReadLine();
            int a;
            int sum = 0;

            for (int i = 0; i < S.Length; i++)
            {
                if (int.TryParse(S.Substring(i, 1), out a))
                {
                    sum += a;
                }
            }

            Console.WriteLine(sum);
        }
    }
}