#include <iostream>
#include <string>

using namespace std;

int main () {
  string s;
  cin >> s;

  int ans = s[0] - '1';
  ans += 9 * ((int) s.size() - 1);

  int dans = 0;
  for (char c : s) {
    dans += c - '0';
  }
  
  cout << max(ans, dans) << endl;
}

### Prompt

Construct a Cpp code solution to the problem outlined:

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>

using namespace std;

int main () {
  string s;
  cin >> s;

  int ans = s[0] - '1';
  ans += 9 * ((int) s.size() - 1);

  int dans = 0;
  for (char c : s) {
    dans += c - '0';
  }
  
  cout << max(ans, dans) << endl;
}

```