#include <bits/stdc++.h>

using namespace std;

int main () {
	string s;
	cin >> s;
	int ans = (s.size () - 1) * 9;
	int ok = 0;
	for (int i = 1;i < s.size ();i ++) if (s[i] != '9') ok = 1;
	ans += (s[0] - '0') - ok;
	cout << ans;
	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 <bits/stdc++.h>

using namespace std;

int main () {
	string s;
	cin >> s;
	int ans = (s.size () - 1) * 9;
	int ok = 0;
	for (int i = 1;i < s.size ();i ++) if (s[i] != '9') ok = 1;
	ans += (s[0] - '0') - ok;
	cout << ans;
	return 0;
}
```