using System;

class Program {
    static void Main() {
        char[] charArry = Console.ReadLine().ToCharArray();
        int sum = 0;
        for (int i = 0; i < charArry.Length; i++) {
            if (char.IsDigit(charArry[i])) {
                sum += int.Parse(charArry[i].ToString());
            }
        }
        Console.WriteLine(sum);
    }
}