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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;


public class Main {
	
	public static void main(String[] args) throws IOException {
		InputStreamReader reader = new InputStreamReader(System.in, StandardCharsets.UTF_8);
	    BufferedReader in = new BufferedReader(reader);
		String s = in.readLine();
		long n = Long.parseLong(s);
		
		long max = addNumbers(n);
		
		long tmp = n;
		long tmp2;
		while(tmp > n/10) {
			tmp2 = addNumbers(tmp);
			if(tmp2 > max) max = tmp2;
			tmp--;
		}
		System.out.println(max);
	}

	private static int addNumbers(long n) {
		String s = "" +n;
		char[] c = s.toCharArray();
		int sum = 0;
		for(int i = 0; i < c.length; i++) {
			sum += Character.getNumericValue(c[i]);
		}
		return sum;
	}
	

}