#include <iostream>
#include <string>

using namespace std;

int main(){
    string N;
    cin >> N;
    int sum = 0;
    for(auto c : N) sum += c - '0';
    cout << max(sum, (int)((N.length() - 1)*9 + N[0] - '1')) << "\n";
}
### Prompt

Please formulate 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>

using namespace std;

int main(){
    string N;
    cin >> N;
    int sum = 0;
    for(auto c : N) sum += c - '0';
    cout << max(sum, (int)((N.length() - 1)*9 + N[0] - '1')) << "\n";
}
```