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 maximumsumofdigits {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		long n = in.nextLong();
		String s = n+"";
		String other ="0";
		for (int i=1; i<s.length(); i++) {
			other+="9";
		}
		System.out.println(getSum(n-Long.parseLong(other))+getSum(Long.parseLong(other)));
	}

	public static int getSum(long n) {
		String s = n+"";
		int res =0;
		for(int i=0;i<s.length();i++) {
			res+=Integer.parseInt(s.substring(i,i+1));
		}
		return res;
	}
}