Three customers, A, B, and C, ordered the shopkeeper to prepare breakfast, and the shopkeeper fell asleep after making steamed buns. The next day, the shopkeeper steamed the steamed buns and put them on the table in the shop without calling the guests. A wakes up, divides the steamed buns into three portions, and leaves after eating his own portion; B divides the steamed buns into three portions after getting up, and leaves after eating his own portion; took his share. At this time, there are still 8 steamed buns left on the table. May I ask how many steamed buns the shopkeeper has prepared for them?
有甲、乙、丙三个客人在吩咐店主准备早餐，店主做完馒头之后就睡下了．第二天，店主将馒头蒸熟后就放在店中的桌子上，并没有去叫客人．甲起床后，将馒头分成三份，吃完自己一份就走了；乙起床后又将馒头分成三份，吃完自己的一份也走了；丙起床后也将馒头分成三份，吃了自己的一份．这时桌子上还剩下8个馒头，试问店主一共为他们准备了多少馒头？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) * (1/3)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/3) * (1/3) * (1/3)</gadget>
<output>1/27 = around 0.037037</output>

<gadget id="calculator">(1/9) - (1/3) - (1/3) - (1/3) - (1/27)</gadget>
<output>-25/27 = around -0.925926</output>

<gadget id="calculator">1 + (1/9) + (1/9) + (-25/27)</gadget>
<output>8/27 = around 0.296296</output>

<gadget id="calculator">8 / (8/27)</gadget>
<output>27</output>

<result>27</result>