#include<iostream>
#include <algorithm>
using namespace std;
int ans1,ans2;
int main(){
    long long n,num=1;
	cin>>n;
	for(long long i=n;i;i/=10){
      ans1+=i%10;
      num*=10;
    }
	num/=10;
	for(long long i=n/num*num-1;i;i/=10) ans2+=i%10;
    cout<<max(ans1,ans2)<<endl;
}
### Prompt

Create a solution in cpp for 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>
#include <algorithm>
using namespace std;
int ans1,ans2;
int main(){
    long long n,num=1;
	cin>>n;
	for(long long i=n;i;i/=10){
      ans1+=i%10;
      num*=10;
    }
	num/=10;
	for(long long i=n/num*num-1;i;i/=10) ans2+=i%10;
    cout<<max(ans1,ans2)<<endl;
}
```