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

int main(){
  cin >> s;
  bool flg = true;
  for(int i=1;i<s.size();i++) {if (s[i]!='9') flg=false;}
  int ans = (s[0]-'1') + 9 * (s.size()-1) + (flg);
  cout << ans << endl;
  return 0;
}
### Prompt

Create a solution in Cpp for 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;
string s;

int main(){
  cin >> s;
  bool flg = true;
  for(int i=1;i<s.size();i++) {if (s[i]!='9') flg=false;}
  int ans = (s[0]-'1') + 9 * (s.size()-1) + (flg);
  cout << ans << endl;
  return 0;
}
```