#include <bits/stdc++.h>
using namespace std;
int main () {
  string S;
  cin >> S;
  long ans = S.at(0) - '0' - 1, sub = 0; 
  ans += 9 * (S.size() - 1);
  for(char a: S)sub += a - '0';
  cout << max(sub, ans) << endl;
}

### Prompt

Please provide a cpp coded solution 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 () {
  string S;
  cin >> S;
  long ans = S.at(0) - '0' - 1, sub = 0; 
  ans += 9 * (S.size() - 1);
  for(char a: S)sub += a - '0';
  cout << max(sub, ans) << endl;
}

```