To bake 3 cakes, both sides of the cake must be baked. There is a pot that can only bake two cakes at a time, and it takes 3 minutes to bake one side. How many minutes does it take at least to bake all the cakes.
要烙3张饼，饼的两面都要烙，有一口锅一次只能烙两张饼，烙好一面需要3分钟．最少需要多少分钟能烙好所有的饼．
<gadget id="calculator">3 + 3 + 3</gadget>
<output>9</output>

<result>9</result>