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.io.*;

public class SumOfDigits {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Long n,mid,b,res;
        int i;

        n = Long.parseLong(br.readLine());
        int num = digits(n);
        Long a = 0L;

        for(i=0;i<num-1;i++){
            a = a*10+9;
        }
        b = n-a;

        res = f(a) + f(b);
        System.out.println(res);
    }
    public static Long f(Long a){
        Long sum = 0L;
        while(a>0){
            sum = sum + a%10;
            a = a/10;
        }
        return sum;
    }
    public static int digits(Long n){
        int num = 0;
        while(n > 0){
            n = n/10;
            num++;
        }
        return num;
    }
}