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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class maximum_sum_of_digit {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     String sen=br.readLine();
     String res="";
     long num=sen.charAt(0)-48;
     num-=1;
     res=num+"";
     for(int i=0;i<sen.length()-1;i++){
    	 res+="9";
     }
     long a=Long.parseLong(res);
     long b=Long.parseLong(sen)-a;
    
     long result=sumOfDigits(a)+sumOfDigits(b);
     System.out.println(result);
     
     
	}
	public static long sumOfDigits(long num) 
    {
        long sum = 0;

        while (num > 0)
        {
            sum = sum + num % 10;
            num = num / 10;
        }

       

        return sum;
    }

}