#include<iostream>
#include<string>
using namespace std;

int main(){
  string s;cin>>s;
  bool flag=true;
  for(int i=1;i<(int)s.size();i++)if(s[i]!='9'){
    flag=false;
    break;
  }
  cout<<9*(int)(s.size()-1)+(int)(s[0]-'0')-(flag?0:1)<<endl;
  return 0;
}
### 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<iostream>
#include<string>
using namespace std;

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