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

namespace ConsoleApplication42
{
    class Program
    {
        static void Main(string[] args)
        {
            int sum = 0;
            using (StreamReader sr = new StreamReader("D:\\New.txt"))
            {
                int x = int.Parse(sr.ReadLine());
                while (x != 0)
                {
                    sum += x % 10;
                    x /= 10;
                }
                Console.WriteLine(sum);
            }
        }
    }
}