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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        long s = n;
        int k = 0;
        while(s != 0){
            s = s / 10;
            k++;
        }
        if(n < 10){
            System.out.println(n);
        }else{
            if(Math.pow(10 , k) - 1 == n){
                System.out.println(9 * k);
            }else{
                int x = (int)(n / (long)Math.pow(10 , k - 1));
                System.out.println(9 * k + x - 10);
            }
        }
        
    }
}