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

using namespace std;

int main()
{
  string N;
  cin >> N;
  int ans = N[0] - '0' - 1 + 9 * (N.size() - 1), tmp = 0;
  for (char t : N)
    tmp += t - '0';
  cout << max(ans, tmp) << endl;

  return 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 <bits/stdc++.h>
#include <assert.h>

using namespace std;

int main()
{
  string N;
  cin >> N;
  int ans = N[0] - '0' - 1 + 9 * (N.size() - 1), tmp = 0;
  for (char t : N)
    tmp += t - '0';
  cout << max(ans, tmp) << endl;

  return 0;
}

```