Problem: You are given a positive integer n.

Let S(x) be sum of digits in base 10 representation of x, for example, S(123) = 1 + 2 + 3 = 6, S(0) = 0.

Your task is to find two integers a, b, such that 0 ≤ a, b ≤ n, a + b = n and S(a) + S(b) is the largest possible among all such pairs.

Input

The only line of input contains an integer n (1 ≤ n ≤ 10^{12}).

Output

Print largest S(a) + S(b) among all pairs of integers a, b, such that 0 ≤ a, b ≤ n and a + b = n.

Examples

Input

35


Output

17


Input

10000000000


Output

91

Note

In the first example, you can choose, for example, a = 17 and b = 18, so that S(17) + S(18) = 1 + 7 + 1 + 8 = 17. It can be shown that it is impossible to get a larger answer.

In the second test example, you can choose, for example, a = 5000000001 and b = 4999999999, with S(5000000001) + S(4999999999) = 91. It can be shown that it is impossible to get a larger answer.

Solution (in JAVA):

Solution:

import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        long number = in.nextLong();
            String a = String.valueOf(number);
            StringBuilder no = new StringBuilder();
            int flag=0;
            no.append(Integer.parseInt(String.valueOf(a.charAt(0)))-1);
            for(int i=0 ; i<a.length()-1 ; i++) {
                no.append('9');
                flag++;
            }
            long n = number-Long.parseLong(no.toString());
            int sum= Integer.parseInt(String.valueOf(a.charAt(0)))-1;
            sum+= flag*9;
            for(int i=0 ; i<String.valueOf(n).length() ; i++)
                sum+=Integer.parseInt(String.valueOf(String.valueOf(n).charAt(i)));
            System.out.println(sum);
    }
}