#include <bits/stdc++.h>
using namespace std;

typedef long long s64;

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

	int n = s.length();
	int a = s[0] - '0';

	int m = 0;
	for (int i = 1; i < n; ++i)
		m += s[i] == '9';

	cout << 9 * (n - 1) + a - (m != n - 1) << endl;

	return 0;
}
### Prompt

Develop a solution in Cpp 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 <bits/stdc++.h>
using namespace std;

typedef long long s64;

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

	int n = s.length();
	int a = s[0] - '0';

	int m = 0;
	for (int i = 1; i < n; ++i)
		m += s[i] == '9';

	cout << 9 * (n - 1) + a - (m != n - 1) << endl;

	return 0;
}
```