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.*;
import java.math.*;
import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;

public class Dupa {
	static long f(long x) {
		long z = 9;
		while(z <= x) {
			z *= 10;
			z += 9;
		}
		return z/10;
	}
	static int count(long x) {
		int res = 0;
		while (x > 0) {
			res += x % 10;
			x = x/10;
		}
		return res;
	}
	
	public static final void main(String[] args) {
		Scanner s = new Scanner(System.in);
		long x = s.nextLong();
		System.out.println("" + (count(f(x)) + count(x - f(x))));
	}
}