#include <iostream>
std::string s;

long long unsigned solve(long long i){
    if(i >= s.size()) return 0;
    return std::max(s[i]-'0'+solve(i+1), (long long)s[i]-'1'+9*(s.size()-i-1));
}

int main() {
    int sum = 0;
    std::cin >> s;
    std::cout << solve(0);
}
### 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>
std::string s;

long long unsigned solve(long long i){
    if(i >= s.size()) return 0;
    return std::max(s[i]-'0'+solve(i+1), (long long)s[i]-'1'+9*(s.size()-i-1));
}

int main() {
    int sum = 0;
    std::cin >> s;
    std::cout << solve(0);
}
```