import java.util.*;
import static java.lang.System.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		String s = sc.next();
		int total = 0;
		int temp;
		for (int i=0; i<s.length(); i++) {
			temp = Character.getNumericValue(s.charAt(i));
			if (temp==0) {total += 10;}
			else {total += temp;}
		}
		out.println(total);
	}
}