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 _0981MaximumSumofDigits {
	static long sumOfDigits(long a) {
		long sum=0;
		while(a>0) {
			sum+=a%10;
			a/=10;
		}
		return sum;
	}

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		long n=sc.nextLong();
		long a=0;
		long b=0;
		
		long up=1;
		while(n>=up) {
			up=up*10;
		}
		up/=10;
		up--;
		a=up;
		b=n-up;
		System.out.println(sumOfDigits(a)+sumOfDigits(n-a));
	}

}