#include <bits/stdc++.h>

using namespace std;
using ll = long long;

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

### 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;
using ll = long long;

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

```