import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		String s = sc.next();
		int sum = 0;
		for (int i=0; i<s.length(); i++) {
			if (s.charAt(i)>=49 && s.charAt(i)<=57) {
				String temp = String.valueOf(s.charAt(i));
				sum += Integer.parseInt(temp);
			}
		}
		System.out.println(sum);
	}
}