#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main()
{
	string N;
	cin >> N;
	int ans = N[0] - '0' + 9 * (N.size() - 1);
	if (count(N.begin() + 1, N.end(), '9') != N.size() - 1) {
		--ans;
	}
	cout << ans << endl;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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>
#include <algorithm>

using namespace std;

int main()
{
	string N;
	cin >> N;
	int ans = N[0] - '0' + 9 * (N.size() - 1);
	if (count(N.begin() + 1, N.end(), '9') != N.size() - 1) {
		--ans;
	}
	cout << ans << endl;
}

```