#include<bits/stdc++.h>
using namespace std;
#define int long
signed main(){
  int n,r=0;
  cin>>n;
  while(n){
    if(n>9&&n%10<9)n-=n%10+1;
    r+=n%10,n/=10;
  }
  cout<<r;
}
### Prompt

Please create a solution in cpp 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;
#define int long
signed main(){
  int n,r=0;
  cin>>n;
  while(n){
    if(n>9&&n%10<9)n-=n%10+1;
    r+=n%10,n/=10;
  }
  cout<<r;
}
```