#include <bits/stdc++.h>
using namespace std;

string a;

int main() {
  cin >> a;
  int res = 0, ans = 0;
  for(int i = 0; i < a.size(); i++) {
    res = max(res, (int)(ans + a[i] - '0' - 1 + 9 * (a.size() - i - 1)));
    ans += a[i] - '0';
  }
  printf("%d\n", max(res, ans));
}
### Prompt

Construct a CPP code solution to the problem outlined:

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;

string a;

int main() {
  cin >> a;
  int res = 0, ans = 0;
  for(int i = 0; i < a.size(); i++) {
    res = max(res, (int)(ans + a[i] - '0' - 1 + 9 * (a.size() - i - 1)));
    ans += a[i] - '0';
  }
  printf("%d\n", max(res, ans));
}
```