#include <iostream>
#include <string>

using namespace std;

int main() {
	string N,K;
	cin >> N;
	
	bool all9 = true;
	for (int i = 1; i < N.length(); ++i) {
		if (N[i] != '9') {
			all9 = false;
		}
	}
	
	cout << (N[0] - '0') + 9 * (N.length() - 1) - (all9 ? 0 : 1);
	return 0;
}
### Prompt

Develop a solution in Cpp to the problem described below:

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>

using namespace std;

int main() {
	string N,K;
	cin >> N;
	
	bool all9 = true;
	for (int i = 1; i < N.length(); ++i) {
		if (N[i] != '9') {
			all9 = false;
		}
	}
	
	cout << (N[0] - '0') + 9 * (N.length() - 1) - (all9 ? 0 : 1);
	return 0;
}
```