using System;
using System.Linq;

namespace No289
{
    class Program
    {
        static void Main(string[] args)
        {
            var S = Console.ReadLine();
            var result = S.Select(c =>
            {
                int tmp;
                return int.TryParse(new string(c, 1), out tmp) ? tmp : 0;
            })
            .Sum();

            Console.Write(result);
        }
    }
}