import java.util.Scanner;

public class No289 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		String[] arr = S.split("");

		int sum = -1;
		for(String s:arr) {
			try {
				sum += Integer.parseInt(s);
			} catch(NumberFormatException e) {

			}
		}

		System.out.println(sum+1);
	}

}