A piece of rope just encloses a rectangle with a length of 5 cm and a width of 3 cm. How long is the rope?
一根绳子刚好围成一个长5厘米、宽3厘米的长方形，这根绳子有多长？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>