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

int main() {
    string s;cin >> s;
    int r=0; for (auto c:s) r += c-'0';
    int t; t = s[0] - '0' - 10 + 9 * s.length();
    cout << max(r,t) << endl;
    return 0;
}
### 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<algorithm>
using namespace std;

int main() {
    string s;cin >> s;
    int r=0; for (auto c:s) r += c-'0';
    int t; t = s[0] - '0' - 10 + 9 * s.length();
    cout << max(r,t) << endl;
    return 0;
}
```