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.*;

public class MaxSum {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String N = sc.next();
        int len = N.length();
        int values[] = new int[len];
        int sum = 0;
        int carry = 0;
        for (int i = 0 ; i < len; i++) {
            values[i] = N.charAt(len-i-1)-'0'-carry;
            if (values[i] == 9) {
                sum += 9;
                carry = 0;
            }
            else if (i == len-1) {
                if (values[i] ==0) {break;}
                else {sum += values[i];}
            } 
            else {
                sum += values[i];
                sum += 10;
                carry = 1;
            }
            //System.out.println(sum);
        }
        System.out.println(sum);
        sc.close();
    }
}