#include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int main(){
    long long j;
    int res=0;
    cin>>j;

    j++;
    while(j>9){
        res += 9;
        j /= 10;
    }
    res += (j-1);

    cout<<res<<"\n";
}

### Prompt

Please create a solution in CPP 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>
#include<string>
#include<algorithm>
using namespace std;

int main(){
    long long j;
    int res=0;
    cin>>j;

    j++;
    while(j>9){
        res += 9;
        j /= 10;
    }
    res += (j-1);

    cout<<res<<"\n";
}

```