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 scan = new Scanner(System.in);
		
		long target = scan.nextLong();
		if (target == 1) {
			System.out.println(1);
		} else {
			long value = 0;
			String string = "";
			while (value < target) {
				value = value * 10 + 9;
				string += "9";
			}
			if (value > target) {
				string = string.substring(1);
				// have less value
				if (Long.toString(target).charAt(0) != '1') {
					string = (char) (Long.toString(target).charAt(0) - 1) + "" + string;
				}
			}
			long value1 = Long.parseLong(string);
			long value2 = target - value1;
			long ans = 0;
			while (value1 > 0) {
				ans += (value1 % 10);
				value1 /= 10;
			}
			while (value2 > 0) {
				ans += (value2 % 10);
				value2 /= 10;
			}
			System.out.println(ans);
		}
		
	}
	
    
}