#include <bits/stdc++.h>
#define int long long
using namespace std;

signed main(){
  int N;
  cin>>N;
  int ll=N;
  int hh=0;
  int out=0;
  while(ll>=10){
    if(ll%10!=9)out++;
    ll/=10;
    hh++;
  }
  int ans=hh*9+ll-1;
  if(out==0)ans++;
  cout<<ans<<endl;
}

### Prompt

Construct a CPP code solution to the problem outlined:

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>
#define int long long
using namespace std;

signed main(){
  int N;
  cin>>N;
  int ll=N;
  int hh=0;
  int out=0;
  while(ll>=10){
    if(ll%10!=9)out++;
    ll/=10;
    hh++;
  }
  int ans=hh*9+ll-1;
  if(out==0)ans++;
  cout<<ans<<endl;
}

```