#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;cin>>s;
  if(s.length()==1){cout<<s[0]-'0';return 0;}
  int currsum=0;
  int n = s.length();
  for(int i=0;i<n;i++)currsum+=s[i]-'0';
  cout<<max(currsum,(n-1)*9+s[0]-'0'-1);
}
### Prompt

Your challenge is to write 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(){
	string s;cin>>s;
  if(s.length()==1){cout<<s[0]-'0';return 0;}
  int currsum=0;
  int n = s.length();
  for(int i=0;i<n;i++)currsum+=s[i]-'0';
  cout<<max(currsum,(n-1)*9+s[0]-'0'-1);
}
```