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

int main(){
	string s;
	cin>>s;
	int a=s[0]-'0';
	if(s.size()>1&&s[s.size()-1]!='9'){
		cout<<(s.size()-1)*9+a-1<<endl;
	}
	else if(s.size()>1){
		cout<<(s.size()-1)*9+a<<endl;
	}
	else{
		cout<<a<<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;

int main(){
	string s;
	cin>>s;
	int a=s[0]-'0';
	if(s.size()>1&&s[s.size()-1]!='9'){
		cout<<(s.size()-1)*9+a-1<<endl;
	}
	else if(s.size()>1){
		cout<<(s.size()-1)*9+a<<endl;
	}
	else{
		cout<<a<<endl;
	}
}

```