#include <bits/stdc++.h>
using namespace std;
 
int main(){
    string str;
    cin >> str;

    int res1 = 0;
    for(char c : str){
        res1 += c - '0';
    }
    int res2 = (str.length()-1) * 9 + str[0] -'1';
    cout << max(res1,res2) << endl;

    return 0;
}
### 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 <bits/stdc++.h>
using namespace std;
 
int main(){
    string str;
    cin >> str;

    int res1 = 0;
    for(char c : str){
        res1 += c - '0';
    }
    int res2 = (str.length()-1) * 9 + str[0] -'1';
    cout << max(res1,res2) << endl;

    return 0;
}
```