#include<iostream>
using namespace std;

int main(){
  string N;
  cin >> N;

  int ans = 0, ans1 = 0, ans2 = 0;
  for(auto c: N){
    ans1 += c - '0';
  }
  ans2 = (N[0] - '0' - 1) + (N.length() - 1) * 9;

  ans = max(ans1, ans2);

  cout << ans << endl;
  
}


### Prompt

Construct a Cpp code solution to the problem outlined:

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<iostream>
using namespace std;

int main(){
  string N;
  cin >> N;

  int ans = 0, ans1 = 0, ans2 = 0;
  for(auto c: N){
    ans1 += c - '0';
  }
  ans2 = (N[0] - '0' - 1) + (N.length() - 1) * 9;

  ans = max(ans1, ans2);

  cout << ans << endl;
  
}


```