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;

public class max_sum_digits
{
    public static void main(String[] args) 
    {
        Scanner sc=new Scanner(System.in);
        long n=sc.nextLong();
        long x=0,i=1;
        int a1=0,a2=0;
        while(n>=(x+(i*9)))
        {
            x+=i*9;
            i*=10;
        }
        n-=x;
        while(true)
        {
            if(n>0)
            {
                a1+=n%10;
                n/=10;
            }
            if(x>0)
            {
                a2+=x%10;
                x/=10;
            }
            if(n<=0 && x<=0)
                break;
        }
        System.out.print(a1+a2);
        sc.close();    
    }
}