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 Main {

	public static void main(String[] args) {
		Scanner cin = new Scanner(System.in);
		long n = cin.nextLong();
		String str = String.valueOf(n);
		if(str.length() == 1)
			System.out.println(n);
		else {
			long tmp = 0;
			for(int i = 1;i < str.length();i++)
				tmp = tmp * 10 + 9;
			long ans = num(tmp) + num(n - tmp);
			System.out.println(ans);
		}
	}

	static int num(long a) {
		int res = 0;
		while (a > 0) {
			res += a % 10;
			a /= 10;
		}
		return res;
	}
}