#include <iostream>
using namespace std;
long long n;
int main(void){
    cin>>n;
    n++;
    int ans=0;
    while(n/10>=1){
        n/=10;
        ans++;
    }
    cout<<n+9*ans-1<<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>
using namespace std;
long long n;
int main(void){
    cin>>n;
    n++;
    int ans=0;
    while(n/10>=1){
        n/=10;
        ans++;
    }
    cout<<n+9*ans-1<<endl;
    
}

```