You can only bake 2 cakes at most at a time, both sides must be baked, each side takes 2 minutes, and 4 cakes need to be baked, how many minutes can be baked at least.
每次最多只能烙2饼，两面都要烙，每面2分钟，要烙4张饼，最少多少分钟才能烙完．
<gadget id="calculator">2 * 2 * 2</gadget>
<output>8</output>

<result>8</result>