#include<bits/stdc++.h>

using namespace std;
using ll = long long;


int main()
{
	string s; cin >> s;
	int n = s.size();
	int cur = 0;
	for(auto i : s) cur += i - '0';
	cout << max( (s.front() - '1') + 9 * (n - 1), cur) << endl;
}
### Prompt

Generate 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<bits/stdc++.h>

using namespace std;
using ll = long long;


int main()
{
	string s; cin >> s;
	int n = s.size();
	int cur = 0;
	for(auto i : s) cur += i - '0';
	cout << max( (s.front() - '1') + 9 * (n - 1), cur) << endl;
}
```