#include <iostream>
using namespace std;
int main(){
  string s;cin>>s;
  int sm = 0;
  for(int i = 0; s.size() > i; i++){
    sm += s[i]-'0';
  }
  cout << max((int)(s.size()-1)*9+s[0]-'0'-1,sm) << endl;
}
### Prompt

Develop a solution in Cpp to the problem described below:

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>
using namespace std;
int main(){
  string s;cin>>s;
  int sm = 0;
  for(int i = 0; s.size() > i; i++){
    sm += s[i]-'0';
  }
  cout << max((int)(s.size()-1)*9+s[0]-'0'-1,sm) << endl;
}
```