#include <bits/stdc++.h>
using namespace std;

int main() {
	string s;
	cin >> s;
	cout << (s[0] - '0') + 9 * (s.size() - 1) - (s.substr(1, s.size() - 1) != string(s.size() - 1, '9')) << 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 <bits/stdc++.h>
using namespace std;

int main() {
	string s;
	cin >> s;
	cout << (s[0] - '0') + 9 * (s.size() - 1) - (s.substr(1, s.size() - 1) != string(s.size() - 1, '9')) << endl;
	return 0;
}
```