batch of T-shirts came in from Huanhuan Clothing Store, and they sold (1/3) of the total number on the first day. If they sold 18 more pieces, they would just sell (1/2) of the total number. How many T-shirts did they buy in total? (Only the column formula does not count)
欢欢服装店进来一批T恤衫，第一天卖出总数的(1/3)，如果再卖18件，就正好卖出总数的(1/2)，一共进了多少件T恤衫？(只列式不计算)
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">18 / (1/6)</gadget>
<output>108</output>

<result>108</result>