Marisa's mushroom shop is running a special promotion: exchanging $k$ mushroom stems will earn you a new mushroom. Currently, you have $n$ mushrooms. You consume one mushroom every day. How many days will it take until you run out of mushrooms?
### Input
- One line containing two integers: $n$ and $k$.
### Output
- A single integer representing the number of days before you run out of mushrooms.
### Constraints
- $1 \le n \le 10^5$.
- $2 \le k \le 10^5$.
### Sample test
Input:
```
10 3
```
Output:
```
14
```
