#include<iostream>
#include<string.h>
#include<string>
using namespace std;
int main()
{
	long long n;
	while (cin >> n)
	{
		long long m=0;
		n++;
		while (n > 9)
		{
			m += 9;
			n = n / 10;
		}
		cout << m + n - 1 << endl;
	}
	return 0;
}
### Prompt

Construct a Cpp code solution to the problem outlined:

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.

Examples

Input

100


Output

18


Input

9995


Output

35


Input

3141592653589793


Output

137

### Response

```cpp
#include<iostream>
#include<string.h>
#include<string>
using namespace std;
int main()
{
	long long n;
	while (cin >> n)
	{
		long long m=0;
		n++;
		while (n > 9)
		{
			m += 9;
			n = n / 10;
		}
		cout << m + n - 1 << endl;
	}
	return 0;
}
```