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 CF_1060_B_MAXIMUM_SUM_OF_DIGITS {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long n = sc.nextLong();

		long a = 0L;

		while (a * 10 + 9 <= n) {
			a *= 10;
			a += 9;
		}
		
		for(int i = 9 ; i >= 1 ; i--)
			if(Long.parseLong(i+""+a) <= n) {
				a = Long.parseLong(i+""+a);
				break ; 
			}
		
		long b = n - a  ;
		
		System.out.println(sumDigits(a) + sumDigits(b));
		
		
	}
	static int sumDigits (long x)
	{
		int ans = 0 ;
		while(x > 0)
		{
			ans += x % 10  ;
			
			x/=10;
		}
		
		return ans ; 
		
	}
}