using System;
using System.Text.RegularExpressions;
public class Program
{
    public static void Main()
    {
        string str = Console.ReadLine() ?? string.Empty;

        string change = Regex.Replace(str, @"[^0-9]", "");
        //Console.WriteLine(change);

        int count = 0;
        for (int i = 0; i < change.Length; i++)
        {
            int num = int.Parse(change.Substring(i,1));
            count += num;
        }
        Console.WriteLine(count);
    }
}