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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>

#define INF 0x3f3f3f3f
#define NINF -0x3f3f3f3f

using namespace std;

typedef pair<int,int> pii;

char str[20];

int main (int argc, char const* argv[])
{
	scanf("%s",str);
	
	int len = strlen(str);
	int c9 = count(str,str+len,'9');
	
	if (c9 == len)
	{
		printf("%d\n",c9*9);
	}
	else
	{
		int total = (str[0]-'0')-1 + (len-1)*9;
		printf("%d\n",total);
	}
		
	return 0;
}