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 ProblemB {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		scan.close();
		String s = Long.toString(n);
		int ans = 0;
		int k = 0;
		long m = 0;
		if(n == 0) {
			System.out.println(0);
			System.exit(0);
		}
		for(int i = 0; i < 100; i++) {
			s = Long.toString(n);
			int l = s.length();
			int t = Integer.parseInt(s.substring(l - 1, l));
			if(l == 1) {
				ans += n;
				System.out.println(ans);
				System.exit(0);

			}
			if(t == 9) {
				ans += 9;
				m =  9;
				n = n - m;
				n = n / 10;
			}else {
				ans += 9 + t + 1;
				m = (10 + t);
				n = n - m;
				n = n / 10;
			}
			k++;
			//System.out.println(n);
		}
		System.out.println(ans);
	}
}