class Program
{
    static void Main(string[] args)
    {
        string input = Console.ReadLine()!;
        int sum = 0;

        foreach (char c in input)
        {
            if (char.IsDigit(c))
            {
                int num = (int)char.GetNumericValue(c);
                sum += num;
            }
        }

        Console.WriteLine(sum);
    }
}