Use iron wire to form a rectangular frame with a length of 8 cm and a width of 4 cm. What is the minimum length of wire?
用铁丝围成一个长8厘米、宽4厘米的长方形框架，至少要用多长的铁丝？
<gadget id="calculator">8 + 4</gadget>
<output>12</output>

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

<result>24</result>