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 MaximumSumOfDigits{
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        long n=scan.nextLong();


        if(n/10==0)
        {
            System.out.println(n);
            return;
        }
        long num=n;long f=0;
        int numDigits=0;
        while(true){
            numDigits++;
            n=n/10;
            if(n<10){
                numDigits++;
                break;
            }
        }n=n-1;
        for(int i=1;i<numDigits;i++){
            n*=10;
            f=f*10+9;
        }
        f=n+f;
        long g=num-f;
        int sum=0;
        
        while(f>0){
            sum+=f%10;
            f=f/10;
        }
        while(g>0){
            sum+=g%10;
            g=g/10;
        }



        System.out.println(sum);
    }
}