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 <string.h>
#include <math.h>

#define LINE_BUF_SIZE 1024

int main(){

    int i,j,k;
    int length,first;
    long int N;
    char line[LINE_BUF_SIZE];

    fgets(line,sizeof(line),stdin);
    //sscanf(&line[0],"%d",&first);
    
        if(strncmp(&line[0],"2",1)==0){
            first = 2;
        }

        if(strncmp(&line[0],"3",1)==0){
            first = 3;
        }

        if(strncmp(&line[0],"4",1)==0){
            first = 4;
        }

        if(strncmp(&line[0],"5",1)==0){
            first = 5;
        }

        if(strncmp(&line[0],"6",1)==0){
            first = 6;
        }

        if(strncmp(&line[0],"7",1)==0){
            first = 7;
        }

        if(strncmp(&line[0],"8",1)==0){
            first = 8;
        }

        if(strncmp(&line[0],"9",1)==0){
            first = 9;
        }

    length = strlen(line);

    if(strncmp(&line[0],"1",1)==0){
        printf("%d\n",9*(length-2));
    }

    else if(first != 9){
        printf("%d\n",9*(length-2)+(first-1));
    }

    else if(first == 9){
        printf("%d\n",9*(length-2)+(first));
    }

//    printf("%d\n",first);

//    printf("%s\n", line);
//    printf("%ld\n", N);

    return 0;
}