Observe a cuboid and see that the areas of its three sides are 3 square meters, 4 square meters, and 5 square meters respectively. What is the surface area of this cuboid in square meters?
观察一个长方体，看到它的三个面的面积分别是3平方米、4平方米、5平方米，这个长方体的表面积是多少平方米．
<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>