Candles from Stubs

Difficulty: 1100 2000 ms 128 MB

math

You have N candles; burning one leaves a stub, and K stubs can be melted into one fresh candle (which also leaves a stub). How many candles can you burn in total?

Input: one line with two integers N and K.

Output: the total number of candles burned.

Constraints:

• 1 ≤ N ≤ 10¹⁸
• 2 ≤ K ≤ 10⁹

Sample Tests

10 3

14

1 2

1

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