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

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var s = Console.ReadLine();
            int n = s.Where(c => c >= '0' && c <= '9').Select(d=>d-'0').Sum();

            Console.WriteLine(n);
            Console.ReadLine();
        }
    }
}