#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main(){
  ll n,ma=0,c=0,cnt=-1,to;
  cin>>n;
  while(n!=0){
    c+=n%10;
    n/=10;
    cnt++;
    if(n<10&&n!=0){
      to=n;
    }
  }
  cout<<max(c,to-1+9*cnt);
}
  

### 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;
#define ll long long
int main(){
  ll n,ma=0,c=0,cnt=-1,to;
  cin>>n;
  while(n!=0){
    c+=n%10;
    n/=10;
    cnt++;
    if(n<10&&n!=0){
      to=n;
    }
  }
  cout<<max(c,to-1+9*cnt);
}
  

```