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

int main() {
  string s;
  cin >> s;
  bool nine = true;
  for (int i = 1; i < s.size(); i++)
    if (s[i] != '9') nine = false;
  cout << s[0] - '0' + 9 * (s.size() - 1) + (nine ? 0 : -1) << 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 <bits/stdc++.h>
using namespace std;

int main() {
  string s;
  cin >> s;
  bool nine = true;
  for (int i = 1; i < s.size(); i++)
    if (s[i] != '9') nine = false;
  cout << s[0] - '0' + 9 * (s.size() - 1) + (nine ? 0 : -1) << endl;
}

```