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>
int main(){
int i,j,k,x,y,z,flag=0;
char s[100];
scanf("%s",s);
for(i=1;s[i]!='\0';i++)
if(s[i]!='9')
{
flag=1;
break;
}
x=0;
y=strlen(s);
if(flag==1)
x=s[0]-48+9*(y-1)-1;
else
x=s[0]-48+9*(y-1);
printf("%d",x);
return 0;
}