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

int sod(long a) {
  int b = 0;
  while (a > 0) b += a % 10, a /= 10;
  return b;
}

int main() {
  string S;
  cin >> S;
  cout << max(sod(stol(S)), 9 * ((int)S.size() - 1) + (S.front() - '1')) << "\n";
}
### Prompt

Please formulate 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 sod(long a) {
  int b = 0;
  while (a > 0) b += a % 10, a /= 10;
  return b;
}

int main() {
  string S;
  cin >> S;
  cout << max(sod(stol(S)), 9 * ((int)S.size() - 1) + (S.front() - '1')) << "\n";
}
```