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

int main(){
	long long n;cin>>n;
  	int suma=0,sumb=0;
  	while(n>0){
    	suma+=n%10;
      	if(n/10==0){
          sumb+=n%10-1;
        }else{
          sumb+=9;
        }
      	n=n/10;
    }
  cout<<max(suma,sumb)<<endl;
}    
### Prompt

Please provide a cpp coded solution to the problem described below:

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(){
	long long n;cin>>n;
  	int suma=0,sumb=0;
  	while(n>0){
    	suma+=n%10;
      	if(n/10==0){
          sumb+=n%10-1;
        }else{
          sumb+=9;
        }
      	n=n/10;
    }
  cout<<max(suma,sumb)<<endl;
}    
```