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.Arrays;
import java.util.Scanner;

public class Prob {

    public static int cnt(long x) {
        int tot = 0;
        while (x > 0) {
            tot += x % 10;
            x /= 10;
        }
        return  tot;
    }

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();
        long m = n;

        long fake = 0;
        long mul = 1;
        while (n >= 10) {
            fake += (n % 10) * mul;
            mul *= 10;
            n /= 10;
        }
        fake++;
        m = m - fake;

        System.out.println(cnt(m) + cnt(fake));

    }
}