#include<iostream>
using namespace std;
int main(){
    long long a,b,sum=0;
    cin>>a;
    b=0;
    while(a>=10){
       b++;
       sum+=a%10;
       a/=10;
    }
    sum+=a;
    if(sum<a+b*9-1) sum=a+b*9-1;
    cout<<sum<<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<iostream>
using namespace std;
int main(){
    long long a,b,sum=0;
    cin>>a;
    b=0;
    while(a>=10){
       b++;
       sum+=a%10;
       a/=10;
    }
    sum+=a;
    if(sum<a+b*9-1) sum=a+b*9-1;
    cout<<sum<<endl;
    return 0;

}
```