import java.util.Scanner;
import java.lang.Integer;

public class Main {
    public static void main(String[] args) {
    		Scanner sc = new Scanner(System.in);
    		String s = sc.next();
    		int number = 0;
    		
    		
    		for(int i = 0;i < s.length(); i++){
    			if(Character.isDigit(s.charAt(i))){
	    			String intStr = s.replaceAll("[^0-9]","");
	    			number = Integer.parseInt(intStr);
    			}	    		
    		}
    		System.out.println(sumDigits(number));
    		
    }
    
    public static int sumDigits(int n) {
        int sum = 0;
        while (n != 0) {
            sum += n % 10;
            n /= 10;
        }
        return sum;
    }
}