#include <bits/stdc++.h>
using namespace std;
long long n,i,j,c,x,a,b;
bool res=true;
int main(){
  for(cin>>n,x=n;n!=0;i++)n/=10;
  for(;j<i-1;j++){
    if(x%10!=9)res=false;
    c+=9,x/=10;
  }
  if(i==1)cout<<x;
  else cout<<(res?c+x:c+x-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;
long long n,i,j,c,x,a,b;
bool res=true;
int main(){
  for(cin>>n,x=n;n!=0;i++)n/=10;
  for(;j<i-1;j++){
    if(x%10!=9)res=false;
    c+=9,x/=10;
  }
  if(i==1)cout<<x;
  else cout<<(res?c+x:c+x-1);
}
```