#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
  ll N; cin >> N;
  ll tmp = N, ket = 0, lst, ans = 0;
  while(tmp > 0){
    lst = tmp % 10;
    ans += lst;
    tmp /= 10;
    ket++;
  }
  
  cout << max(ans, (ket-1) * 9 + lst - 1) << endl;
}
### 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;
typedef long long ll;

int main(){
  ll N; cin >> N;
  ll tmp = N, ket = 0, lst, ans = 0;
  while(tmp > 0){
    lst = tmp % 10;
    ans += lst;
    tmp /= 10;
    ket++;
  }
  
  cout << max(ans, (ket-1) * 9 + lst - 1) << endl;
}
```