#include<iostream>
using namespace std;
int main(){
	long long s;
	cin>>s;
	int ans=0;
	bool nine=0;
	while(s>=10){
		if(s%10<9)nine=1;
		s/=10;
		ans+=9;
	}
	ans+=s;
	if(nine)ans--;
	cout<<ans<<endl;
}
### Prompt

Create a solution in cpp for 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<iostream>
using namespace std;
int main(){
	long long s;
	cin>>s;
	int ans=0;
	bool nine=0;
	while(s>=10){
		if(s%10<9)nine=1;
		s/=10;
		ans+=9;
	}
	ans+=s;
	if(nine)ans--;
	cout<<ans<<endl;
}
```