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.*;
import java.lang.*;
public class maximumSumOfDigits
{
        
   public static void main(String args[])
     { 
        long s1, s2=0; 
        long k=0; 
        long n=0; 
        int c=0; 
        long sum=0;
        
        Scanner sc= new Scanner(System.in);
        
        n=sc.nextLong();
        k=n;
        
        while(k>=1)
        {
        	c++;
        	k=k/10;
      
        }
 
        for(int i =0; i<c-1; i++)
        {
        	s2= s2 *10 + 9;
        }
    
        s1=n-s2;
    
        while(s1>=1)
        {
        	sum = sum + (s1%10);
        	s1=s1/10;
    
        } 
    
        while(s2>=1)
        {
        	sum = sum + (s2%10);
        	s2=s2/10;
    
        }
    
       System.out.println(sum);
     }	      
}