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;

public class b_1060

{
  public static long jh=0;
  public static  long som(long n)
  {
      
     long w=0;
     while(n/10!=0)
     {
        
       w=w+n%10;
       n= n/10;
       
      
     }
     w=w+n%10;
    
    
     return w;
  }
   public static  long som2(long n)
  {
      
     long w=0,sum=9;
     while(n/10!=0)
     {
        
       w=w+n%10;
       n= n/10;
       sum=sum*10+9;
      
     }
     w=w+n%10;
     sum=sum/10;
    
     return sum;
  }
  
  public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        long  k=sc.nextLong();
        long a,b ,c ,v,s=0,max=0,i=0;
                a=k-som2(k);
                
               
        System.out.println((som(a)+som(som2(k))));
  
    }

}