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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class B {

	public static void main(String[] args) throws IOException {
		InputStreamReader in = new InputStreamReader(System.in);
		BufferedReader buffer = new BufferedReader(in);
		String line = buffer.readLine();
		Long number = Long.parseLong(line);
		if (number < 10) {
			System.out.println(number);
		} else {
			String nines = "";
			Long nineCount = (long) (line.length() - 1);
			for (int i = 0; i < nineCount; i++) {
				nines += '9';
			}
			Long diff = number - Long.parseLong(nines);
			Long result = 9 * nineCount;
			while (diff > 0) {
				result += diff % 10;
				diff /= 10;
			}
			System.out.println(result);
		}
	}

}