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.*;
import java.util.*;
public class MaximumSumofDigits
{
	public static void main(String[] d)
	{
		long n,i;
		String s="";
		Scanner sc=new Scanner(System.in);
		n=sc.nextLong();
		int digi=((int)(Math.log(n)/Math.log(10)));
		for(i=0;i<digi;i++)
		{
			s+="9";
		}
		long f;
		if(s.length()==0)
			f=0;
		else
			f=Long.parseLong(s);
		n-=f;	
		long e=sumdigi(n);
		System.out.println((e+(digi*9)));
		
	}
	 static long sumdigi(long n)
	 {
		 long sum=0;
		 while(n!=0)
		 {
			 sum+=(n%10);
			 n/=10;
		 }
		 return sum;
	 }
}