It is known that a set of adjacent sides of a parallelogram is 5 cm and 3 cm respectively, then what is the perimeter of the parallelogram in cm.
已知一个平行四边形的一组邻边分别是5厘米和3厘米，那么这个平行四边形的周长是多少厘米．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

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

<result>16</result>