#include<bits/stdc++.h>
using namespace std;
int main(){
  long long n;
  int cnt=0,last;
  bool f=true;
  cin>>n;
  while(n!=0){
    if(n/10==0) last=n;
    else if(n%10!=9) f=false;
    cnt++;
    n/=10;
  }
  cout<<((cnt-1)*9+(f?last:last-1))<<endl;
  return 0;
}


### Prompt

Create a solution in CPP for 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(){
  long long n;
  int cnt=0,last;
  bool f=true;
  cin>>n;
  while(n!=0){
    if(n/10==0) last=n;
    else if(n%10!=9) f=false;
    cnt++;
    n/=10;
  }
  cout<<((cnt-1)*9+(f?last:last-1))<<endl;
  return 0;
}


```