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.*;
import java.util.*;

public class Main
{    
    static int getMaxSumOfDigits(long num){
        long multi = (long) Math.pow(10,Math.floor(Math.log10(num)));
        long a = num / multi * multi - 1;
        long b = num - a;
        //System.out.println("a: " + a + "  b: " + b);
        
        int sum = 0;
        while(a != 0)
        {
            sum += (a %10);
            a /= 10;
        }

        while(b != 0)
        {
            sum += (b %10);
            b /= 10;
        }
        return sum;
     }
    
    public static void main(String[] args) throws IOException 
	{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        long n = Long.parseLong(br.readLine());
        int ans = getMaxSumOfDigits(n);
		System.out.println(ans);
    }
}