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

signed main() {
  ios::sync_with_stdio(false);
  string N;
  cin >> N;
  int ans = 0;
  for (char c : N) ans += c - '0';
  cout << max<int>((N.size() - 1) * 9 + N[0] - '1', ans) << endl;
  return 0;
}

### Prompt

In cpp, your task is to solve 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;

signed main() {
  ios::sync_with_stdio(false);
  string N;
  cin >> N;
  int ans = 0;
  for (char c : N) ans += c - '0';
  cout << max<int>((N.size() - 1) * 9 + N[0] - '1', ans) << endl;
  return 0;
}

```