import java.io.*;
import java.util.*;


public class Main_yukicoder656 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		char[] s = sc.next().toCharArray();

		int ans = 0;
		for (char c : s) {
			if (c == '0') {
				ans += 10;
			} else {
				ans += c - '0';
			}
		}

		pr.println(ans);
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}