Weld a cuboid frame with a length of 7cm, a width of 2cm, and a height of 1cm, at least how many centimeters of iron wire should be used.
焊接一个长7cm、宽2cm、高1cm的长方体框架，至少要用多少cm的铁丝．
<gadget id="calculator">7 + 2 + 1</gadget>
<output>10</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>