#include<iostream>
#include<string>
using namespace std;

int main() {
	string s; cin >> s;

	int c = s[0] - '0';

	for (int i = 1; i < s.size(); i++) {
		if (s[i] != '9') {
			c--; break;
		}
	}
	cout << c + 9 * (s.size() - 1) << endl;

	return 0;
}
### Prompt

Your task is to create a Cpp solution to the following problem:

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 s; cin >> s;

	int c = s[0] - '0';

	for (int i = 1; i < s.size(); i++) {
		if (s[i] != '9') {
			c--; break;
		}
	}
	cout << c + 9 * (s.size() - 1) << endl;

	return 0;
}
```