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 Main
{
    public static int sumNumberDigits(String num1,String num2){
        int sum=0;
        for(int i=0;i<num1.length();i++){
            int a=Integer.parseInt(String.valueOf(num1.charAt(i)));  
            sum+=a;
        }
        for(int i=0;i<num2.length();i++){
            int a=Integer.parseInt(String.valueOf(num2.charAt(i)));  
            sum+=a;
        }
        return sum;
    }
	public static void main(String[] args) {
	    Scanner sc = new Scanner (System.in);
        long number = sc.nextLong();
        int sum=0;
        long iter=9;
        while(number>=iter){
            iter=iter*10+9;
        }
        iter=iter/10;
        long f_number=iter,s_number=number-iter;
        sum+=sumNumberDigits(String.valueOf(f_number),String.valueOf(s_number));
        System.out.println(sum);
	}
}