#include<iostream>
using namespace std;
int a=1;string s;
int main()
{
  cin>>s;
  for(int i=1;i<s.size();i++)a&=s[i]=='9';
  cout<<(9*(s.size()-1)+s[0]-'1'+a)<<endl;
}
### 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<iostream>
using namespace std;
int a=1;string s;
int main()
{
  cin>>s;
  for(int i=1;i<s.size();i++)a&=s[i]=='9';
  cout<<(9*(s.size()-1)+s[0]-'1'+a)<<endl;
}
```