If the lengths of two adjacent sides of a parallelogram are 12 cm and 16 cm respectively, what is the perimeter of the parallelogram in cm?
一个平行四边形相邻的两条边长度分别是12厘米和16厘米，这个平行四边形的周长是多少厘米．
<gadget id="calculator">12 + 16</gadget>
<output>28</output>

<gadget id="calculator">28 * 2</gadget>
<output>56</output>

<result>56</result>