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 Coding;

import java.io.*;
import java.util.*;

public class CodeForces {
    public static void main(String[] args) throws IOException {
        Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        long N = n;
        int lastD = 0;
        int len = 0;
        int ans = 0;

        while (n > 0) {
            lastD = (int) (n % 10);
            len++;
            n /= 10;
        }

        long n1 = (long)Math.pow(10, len - 1) * lastD - 1;
        long n2 = N - n1;
        while (n1 != 0 || n2 != 0) {
            ans += n1 % 10 + n2 % 10;
            n1 /= 10;
            n2 /= 10;
        }
        System.out.println(ans);

    }


}