Problem:
Score : 300 points

Problem Statement

Find the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Constraints

1\leq N \leq 10^{16}

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Sample Input 1

100

Sample Output 1

18

For example, the sum of the digits in 99 is 18, which turns out to be the maximum value.

Sample Input 2

9995

Sample Output 2

35

For example, the sum of the digits in 9989 is 35, which turns out to be the maximum value.

Sample Input 3

3141592653589793

Sample Output 3

137

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        if (scanner.hasNextLine()) {
            String line = scanner.nextLine();
            boolean isNotAll9 = false;
            for (int i = 1; i < line.length(); ++i) {
                if (line.charAt(i) != '9') {
                    isNotAll9 = true;
                    break;
                }
            }
            int ret = line.charAt(0) - '0' + 9 * (line.length() - 1);
            if (isNotAll9) {
                --ret;
            }
            System.out.println(ret);
        }
    }
}