#include <bits/stdc++.h>

using namespace std;

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	
	string n;
	
	cin>>n;
	
	cout<<(n.size() - 1) * 9 + n.front() - '0' - (n.find_first_not_of('9', 1) != string::npos)<<'\n';
}

### Prompt

Construct a CPP code solution to the problem outlined:

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()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	
	string n;
	
	cin>>n;
	
	cout<<(n.size() - 1) * 9 + n.front() - '0' - (n.find_first_not_of('9', 1) != string::npos)<<'\n';
}

```