import java.util.Scanner;

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