#include <iostream>
#include <algorithm>

using namespace std;
typedef long long ll;

int main(void) {
	long long h, n, len = -1, sum = 0;
	cin >> n;
	while (n > 0) {
		sum += n % 10;
		len++;
		h = n;
		n /= 10;
	}
	cout << max(h + 9 * len - 1, sum) << "\n";
	return 0;
}
### Prompt

Please create a solution in Cpp 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;
typedef long long ll;

int main(void) {
	long long h, n, len = -1, sum = 0;
	cin >> n;
	while (n > 0) {
		sum += n % 10;
		len++;
		h = n;
		n /= 10;
	}
	cout << max(h + 9 * len - 1, sum) << "\n";
	return 0;
}
```