#include <bits/stdc++.h>

using namespace std;

int main() {
    string n;
    cin >> n;

    int sum = 0;
    for (auto s:n) {
        sum += s - '0';
    }

    auto tmp = (int) ((n[0] - '1') + 9 * (n.size() - 1));
    cout << max(tmp, sum) << endl;
}
### Prompt

In CPP, your task is to solve 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 <bits/stdc++.h>

using namespace std;

int main() {
    string n;
    cin >> n;

    int sum = 0;
    for (auto s:n) {
        sum += s - '0';
    }

    auto tmp = (int) ((n[0] - '1') + 9 * (n.size() - 1));
    cout << max(tmp, sum) << endl;
}
```