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

int main() {
  string s;
  cin>>s;
  int n=s.size();
  int ans=0;
  for(int i=0;i<n;i++){
    ans+=s[i]-'0';
  }
  cout<<max(ans,9*(n-1)+(s[0]-'0')-1)<<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;
  int n=s.size();
  int ans=0;
  for(int i=0;i<n;i++){
    ans+=s[i]-'0';
  }
  cout<<max(ans,9*(n-1)+(s[0]-'0')-1)<<endl;
}

```