Tudor, having made his own tea for far too long, has decided to go to a nearby tea shop to buy some tea.

As every respectable tea shop does, this specific tea shop offers a loyalty program. For every $K$ cups of tea that Tudor buys at the shop, the shop will give him one free cup of tea.

Tudor wants to drink at least $N$ cups of tea. How many cups of tea will he have to buy in order to achieve this goal?

Constraints

$1\le N,K\le {10}^{18}$ - note that 32-bit integers may not be sufficient to solve this problem.

In tests worth 5 marks, $N=K$.

Input Specification

The input will consist of a single line containing two positive integers, $N$ and $K$.

Output Specification

Output, on a single line, the minimum number of cups of tea Tudor needs to buy.

Sample Input

11 10

Sample Output

10

Sample Explanation

This tea shop is very traditional and gives a free cup of tea per 10 bought. If Tudor buys 10 cups of tea, he'll end up with 11, which is perfect.