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: Time Limit Exceeded)


import java.util.*;
import java.util.HashSet;
import java.util.Set;
public class Main{
    public static void main(String[]args){
        Scanner sc=new Scanner(System.in);
        String num=sc.next();
        long nu=Long.parseLong(num);
        Set<Long>all=new HashSet<Long>();
        for(long k=0;k<nu;k++){
        long sum=0;
        char[]s=num.toCharArray();
        long ss[]=new long[num.length()];
        for(long i=0;i<num.length();i++){
            ss[(int)i]=Long.parseLong(""+s[(int)i]);
        }
        for(long i=0;i<num.length();i++){
            sum=sum+ss[(int)i];
        }
        all.add(sum);
        nu--;
        num=String.valueOf(nu);

    }
    long max=0;
    for(long k:all){
        if(k>=max){
            max=k;
        }
    }
    System.out.println(max);
    

       

        
        
        }
       
        
    }