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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System.Linq;using System;
class A{static void Main(){
long a=long.Parse(Console.ReadLine());
  string str=a.ToString();
  bool flag=true;
  for(int i=0;i<str.Length;i++){if(str[i]!='9'){flag=false;}}
  if(flag){Console.WriteLine(str.Length*9);return;}
  else {Console.WriteLine((str.Length-1)*9+int.Parse(str.Substring(0,1)));}
  
}}