import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        int answer = 0;

        Scanner scanner = new Scanner(System.in);
        String s = scanner.next();

        Pattern pattern = Pattern.compile("^[0-9]+$");

        for (char c : s.toCharArray()) {
            String sOfC = String.valueOf(c);
            if (pattern.matcher(sOfC).matches()) {
                int i = Integer.parseInt(sOfC);
                answer += i;
            }
        }

        System.out.println(answer);
    }
}