A pan can hold 3 cakes at a time, a cake has two sides, it takes 1 minute to cook one side, and at least how many minutes it takes to cook 16 cakes.
一只平底锅每次可以放3张饼，一张饼有两面，煎熟一面要1分钟，煎熟16张饼至少要多少分钟．
<result>12</result>