package algo;

import java.util.Scanner;
import java.util.*;

public class sample7 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String N = sc.next();
		char[] c = N.toCharArray();
		int sum = 0;
		for(int i = 0; i < c.length; i++) {
			if(c[i] == '0') {
				sum += 10;
			}
			else {
				sum += Character.getNumericValue(c[i]);
			}
		}
		System.out.println(sum);
	}
}