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

int main() {
  long long int n,ans;
  cin>>n;
  string s=to_string(n);
  ans=(s.at(0)-'0')+(s.size()-1)*9-1;
  for(int i=1;i<s.size();i++){
    if(s.at(i)!='9'){
      cout<<ans<<endl;
      return 0;
    }
  }
  cout<<ans+1<<endl;
}
### Prompt

Please provide a Cpp coded solution 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 <bits/stdc++.h>
using namespace std;

int main() {
  long long int n,ans;
  cin>>n;
  string s=to_string(n);
  ans=(s.at(0)-'0')+(s.size()-1)*9-1;
  for(int i=1;i<s.size();i++){
    if(s.at(i)!='9'){
      cout<<ans<<endl;
      return 0;
    }
  }
  cout<<ans+1<<endl;
}
```