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:
//package CodeForces.B;

import java.util.Scanner;

public class Task1060B {
    public static void main(String[] args) {
        Scanner scn = new Scanner(System.in);
        String n = scn.next();
        long nch = Long.parseLong(n);
        String a = "";
        int sum = 0;
        for(int i = 0; i<n.length()-1; i++){
            a+='9';
            sum+=9;
        }
        if(a.length()==0){
            System.out.println(nch);
            return;
        }
        long ach = Long.parseLong(a);
        String b = String.valueOf(nch-ach);
        for(int i = 0; i<b.length(); i++){
            sum+=Integer.parseInt(String.valueOf(b.charAt(i)));
        }
        System.out.println(sum);
    }
}