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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include<stdio.h>
#include <inttypes.h>

void main(){
  unsigned long long int input = 0;
  unsigned long long int temp = 0;
  int max = 0;
  int num = 0;
  int f = 0;
  scanf("%llu",&input);

  temp = input;
  while(temp){
    num++;
    f = temp%10;
    temp /= 10;
  }
  for(int i = 0; i < num - 1;i++){
    max += 9;
  }
  max += f - 1;

  printf("%d\n", max);

}