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

int main(){
	string s;
	cin>>s;
	long long int ans=0;
	
	for(int i=0;i<s.size();i++){
		ans+=s[i]-'0';
	}
	
	long long tmp=(s.size()-1)*9;
	tmp+=s[0]-'0';
	tmp-=1;
	ans=max(ans,tmp);
	cout<<ans<<endl;
	
	
	
	
}
### Prompt

In cpp, your task is to solve 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;
	long long int ans=0;
	
	for(int i=0;i<s.size();i++){
		ans+=s[i]-'0';
	}
	
	long long tmp=(s.size()-1)*9;
	tmp+=s[0]-'0';
	tmp-=1;
	ans=max(ans,tmp);
	cout<<ans<<endl;
	
	
	
	
}
```