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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author ky112233
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BMaximumSumOfDigits solver = new BMaximumSumOfDigits();
        solver.solve(1, in, out);
        out.close();
    }

    static class BMaximumSumOfDigits {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            long n = in.nextLong();
            long t = 1;
            while (t <= n) t *= 10;
            long temp = n / (t / 10);
            long another = n - (t / 10) * temp + 1;
            temp -= 1;
            long ans = temp;
            long temptemp = n;
            while (temptemp >= 10) {
                ans += 9;
                temptemp /= 10;
            }
            temptemp = another;
            while (temptemp != 0) {
                ans += temptemp % 10;
                temptemp /= 10;
            }
            out.println(ans);
        }

    }
}