#include <bits/stdc++.h>

using namespace std;

int main() {
  long long n;
  cin >> n;
  int ans = 0;
  int cnt = 0;
  while (n >= 10) {
    ans += (int)(n % 10);
    ++cnt;
    n /= 10;
  }
  ans += (int)n;
  ans = max(ans, (int)((n - 1) + 9 * cnt));
  cout << ans << endl;
}

### 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 <bits/stdc++.h>

using namespace std;

int main() {
  long long n;
  cin >> n;
  int ans = 0;
  int cnt = 0;
  while (n >= 10) {
    ans += (int)(n % 10);
    ++cnt;
    n /= 10;
  }
  ans += (int)n;
  ans = max(ans, (int)((n - 1) + 9 * cnt));
  cout << ans << endl;
}

```