import java.util.*;

public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
    String [] s = sc.next().split("");
    int ans = 0;
    for (int i = 0; i < s.length; i++) {
      if (Integer.parseInt(s[i]) == 0) {
        ans += 10;
      } else {
        ans += Integer.parseInt(s[i]);
      }
    }
    System.out.println(ans);
    sc.close();
    }
  }