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.Scanner;
import java.util.*;

public class MaximumSumofDigits {

    public static void main(String[] args) 
	{

        Scanner sc = new Scanner(System.in);

        long y = sc.nextLong();
        long a = 0;
        int x = 0 ;

        while (a * 10 + 9 < y) 
	{
            a = a * 10 + 9;
            x += 9;
        }

        y = y - a;

        while (y > 0) 
	{
            x += y % 10;
            y = y / 10;
        }

        System.out.println(x);
    }
}