If two cuboids with side lengths of 3 cm, 5 cm, and 7 cm are put together to form a cuboid, what is the maximum reduction in their surface area in square centimeters?
棱长分别为3厘米、5厘米、7厘米的两个长方体拼成一个长方体，它们的表面积最多减少多少平方厘米．
<gadget id="calculator">5 * 7 * 2</gadget>
<output>70</output>

<result>70</result>