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: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
  char s[18], t[16];
  int n, sum, i, max = 0;

  scanf("%s", s);
  n = atoi(s);

  while (n > 0) {  
    // 全部の位の数の総和
    t[18] = n;
    sum = 0;
    for (i = 0; i <= 16; i++) {
      sum += t[i];
    }

    if (max < sum) {
      max = sum;
    }
    n--;
  }

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

  return 0;
}