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.*;
public class susbus{
   public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      String s = String.valueOf(n);
//      System.out.println(s);
      long a = largestnine(n);
      long b = n-a;
//     System.out.println(a + " " + b);
      System.out.println(sumDigits(a)+sumDigits(b));
   }
   public static long largestnine(long n){
      int count=0;
      while((Math.pow(10,count+1)-1)<=n) count++;
      return (long) (Math.pow(10,count)-1);
   }
   public static int sumDigits(long n){
      String s=  String.valueOf(n);
      int sum=0;
      for(int i=0;i<s.length();i++){
         sum+=Integer.parseInt(s.substring(i, i+1));
      }
      return sum;
   }
}