Only two fish can be fried at a time, both sides must be fried, one side needs to be fried for 3 minutes, and 5 fishes need to be fried, how many minutes is the minimum required.
一次只能煎两条鱼，两面都要煎，一面要煎3分钟，要煎5条鱼，最少需要多少分钟．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<result>15</result>