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.lang.Math;
public class MaxSum {
  public static void main(String[] args){
    Scanner sc = new Scanner (System.in);
    long n = sc.nextLong();
    int res = 0;
    String s = "" + n;
    int len = s.length() - 1;
    long t = (long)(n - Math.pow(10, len) + 1);
    String s1 = "" + t;

    for(int i = 0; i < s1.length(); i++){
      res += Integer.parseInt(String.valueOf(s1.charAt(i)));
    }

    res += len * 9;
    System.out.println(res);
  }
}