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

int main(){
  int64_t N;
  cin >> N;
  string s=to_string(N);
  s=string(s.size()-1,'9');
  for(int i=9;i>=0;i--){
    if(stoll((char)(i+'0')+s)<=N){
      cout << s.size()*9+i << endl;
      return 0;
    }
  }
  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;

int main(){
  int64_t N;
  cin >> N;
  string s=to_string(N);
  s=string(s.size()-1,'9');
  for(int i=9;i>=0;i--){
    if(stoll((char)(i+'0')+s)<=N){
      cout << s.size()*9+i << endl;
      return 0;
    }
  }
  return 0;
}

```