#include <algorithm>
#include <iostream>

using namespace std;

int main() {
  string S;
  cin >> S;
  cout << S[0] - '1' + (S.size() - 1) * 9 +
              all_of(begin(S) + 1, end(S), [](int x) { return x == '9'; })
       << endl;
}

### 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 <algorithm>
#include <iostream>

using namespace std;

int main() {
  string S;
  cin >> S;
  cout << S[0] - '1' + (S.size() - 1) * 9 +
              all_of(begin(S) + 1, end(S), [](int x) { return x == '9'; })
       << endl;
}

```