#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main(){
string N;
cin >> N;
int i = 0;
for(char t : N)
  i+= t-'0';
int j = N[0] -'0' - 1 + 9 * int(N.size()-1);
cout << max(i,j) << endl;
}
### Prompt

Generate a Cpp solution 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 <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main(){
string N;
cin >> N;
int i = 0;
for(char t : N)
  i+= t-'0';
int j = N[0] -'0' - 1 + 9 * int(N.size()-1);
cout << max(i,j) << endl;
}
```