// 2023 IUSB Programming Competition
// Round 1 Problem 1
// String Mining
// Solution by Liguo Yu

import java.util.Scanner;

public class round1_p1
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        String s = input.nextLine();
        
        int sum = 0;
        for(int i=0; i<s.length(); i++)
        {
            if(Character.isDigit(s.charAt(i)))
            {
                sum = sum + Character.getNumericValue(s.charAt(i));
            }
        }
        
        System.out.println(sum);
    }
}