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

int main() {
  string N;
  cin >> N;
  int ans1 = 0, ans2 = (N[0] - '0' - 1) + (9 * (N.size() - 1));
  for (int i = 0; i < N.size(); i++) ans1 += N[i] - '0';
  cout << max(ans1, ans2) << endl;
}
### 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>
#include <algorithm>
using namespace std;

int main() {
  string N;
  cin >> N;
  int ans1 = 0, ans2 = (N[0] - '0' - 1) + (9 * (N.size() - 1));
  for (int i = 0; i < N.size(); i++) ans1 += N[i] - '0';
  cout << max(ans1, ans2) << endl;
}
```