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;

/**
 *
 * @author izharishaksa
 */
public class C1060B {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String s = N + "";
        char c = s.charAt(0);
        String temp = "0";
        if (c != '1') {
            temp = "" + (c - '1');
        }
        for (int i = 1; i < s.length(); i++) {
            temp += '9';
        }
        long b = Long.parseLong(temp);
        long a = N - b;
        int res = 0;
        while (a > 0) {
            res += a % 10;
            a /= 10;
        }
        while (b > 0) {
            res += b % 10;
            b /= 10;
        }
        System.out.println(res);
    }

}