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 Main {
  public static long sum(long n)
{
  long p=0;
  while(n>0){
    p=p+n%10;
    n=n/10;
  }
  return p;
}
  public static void main(String[] args) {
    Scanner s=new Scanner(System.in);
    long n = s.nextLong();
    if(n<19)
    {
        System.out.println(n);
        return;
    }
    long a=0;
    long p=0;
    for(long i=9;i<n;i=10*i+9)
    {
      p=sum(i)+sum(n-i);
      if(p>a)
      a=p;
    }    
    System.out.println(a);
  }
}