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 olympiads;

import java.util.Scanner;

public class taskB {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    Scanner in = new Scanner(System.in);
    long n = in.nextLong();
    //System.out.println(max);
    long x = 0;
    long sum = 0;
   while (x * 10 + 9 < n) {
	   x = x * 10 + 9;
	   sum += 9;
   }
    long k = n - x;
    System.out.println(sum + sum_number(k));
    in.close();
	}
  public static long sum_number (long k) {
	  long res = 0;
	 while (k >= 10) {
		  
		  res += k % 10;
		  k /= 10;
		  
	  }
	  res += k;
	  return res;
  }
}