#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int64_t N;
  cin >> N;
  N++;
  int nod = 0;
  while (N > 10) {
    N /= 10;
    nod++;
  }
  cout << N - 1 + 9 * nod << '\n';
  return 0;
}

### Prompt

Develop a solution in Cpp to the problem described below:

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() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int64_t N;
  cin >> N;
  N++;
  int nod = 0;
  while (N > 10) {
    N /= 10;
    nod++;
  }
  cout << N - 1 + 9 * nod << '\n';
  return 0;
}

```