using System;
using System.Linq;

class Problem
{
    public static void Main(string[] args)
    {
        var line = Console.ReadLine();
        var ans = 0;
        foreach (var c in line)
        {
            if (c >= '0' && c <= '9') ans += (int) Char.GetNumericValue(c);
        }
        Console.WriteLine($"{ans}");
    }
}