#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
  	cin>>s;
  	int cur=0;
  	for (char c:s){
    	cur+=c-'0';
    }
  	cout<<max(cur,(int)(s[0]-'0'-1+9*(s.size()-1)))<<endl;
  	return 0;
}

### 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 cur=0;
  	for (char c:s){
    	cur+=c-'0';
    }
  	cout<<max(cur,(int)(s[0]-'0'-1+9*(s.size()-1)))<<endl;
  	return 0;
}

```