import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		Main main=new Main();
		main.run();
	}

	void run() {

		Scanner sc=new Scanner(System.in);

		String str=sc.next();

		String[] input=str.split("");

		int sum=0;
		for(String s:input) {

			if(s.equals("0")) {
				sum+=10;
			}else {
				sum+=Integer.valueOf(s);
			}

		}

		System.out.println(sum);



	}
}