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

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

Your task is to create 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 <cstdio>
using namespace std;

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