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: Accepted)

#include<stdio.h>
#include<string.h>
int main()
{
    int len,maxsum,flag,i;
    char str[50];
    while(gets(str)!=NULL)
    {
        flag=1;
        len = strlen(str);
        for(i=1;i<len;i++)
        {
            if(str[i]<'9')
            {
                flag=0;
                break;
            }
        }
        if(flag==0)
            maxsum=9*(len-1)-1+str[0]-'0';
            else
                maxsum=9*(len-1)+str[0]-'0';
        printf("%d\n",maxsum);
    }
    return 0;
}