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

int main() {
  string s;
  cin >> s;
  int t = 0;
  for (auto e : s) t += e - '0';
  int n = s.size(), h = s.front() - '0', r = h + (n - 1) * 9;
  cout << r - (r != t) << endl;
}

### Prompt

Your task is to create a cpp solution 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 s;
  cin >> s;
  int t = 0;
  for (auto e : s) t += e - '0';
  int n = s.size(), h = s.front() - '0', r = h + (n - 1) * 9;
  cout << r - (r != t) << endl;
}

```