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

int main () {
  long N;
  cin >> N;
  int count = 0;
  bool x = true;
  while (N >= 10) {
    if (N%10 != 9) x = false;
    count++;
    N /= 10;
  }
  int ans = N-1+count*9;
  if (x) ans += 1;
  cout << ans << endl;
}
### Prompt

Please create a solution in cpp 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 () {
  long N;
  cin >> N;
  int count = 0;
  bool x = true;
  while (N >= 10) {
    if (N%10 != 9) x = false;
    count++;
    N /= 10;
  }
  int ans = N-1+count*9;
  if (x) ans += 1;
  cout << ans << endl;
}
```