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;

/**
 *
 * @author CHAGO
 */
public class B {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        long n= sc.nextLong();
        long m=n;
        long s=0;
        long a=0;
        long i=1;
        while(n>9){
            a+=9*i;
            i*=10;
            s+=9;
            n/=10;
        }
        a+=i*(n-1);
        s+=n-1;
        long c=m-a;
        while(c>=10){
        s+=c%10;
        c=c/10;
        }
        s+=c;
        System.out.println(s);
    }
}