import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		char[] arr = sc.next().toCharArray();
		int score = 0;
		for (char c : arr) {
		    if (c == '0') {
		        score += 10;
		    } else {
		        score += c - '0';
		    }
		}
		System.out.println(score);
  }
 }