There are a pile of black and white pieces, the number of black pieces is twice the number of white pieces, if 4 black pieces and 3 white pieces are taken out from this pile of pieces at the same time, after how many times of taking out, there will be 1 white piece and 1 black piece There are 18 remaining.
有黑白棋子一堆，其中黑子的个数是白子个数的2倍，如果从这堆棋子中每次同时取出黑子4个，白子3个，那么取出多少次后，白子余1个，而黑子余18个．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">8 / 1</gadget>
<output>8</output>

<result>8</result>