If the lengths of two adjacent sides of a parallelogram are 15cm and 8cm, what is the perimeter of the parallelogram in cm?
一个平行四边形相邻的两条边长是15cm和8cm，这个平行四边形的周长是多少cm．
<gadget id="calculator">15 + 8</gadget>
<output>23</output>

<gadget id="calculator">23 * 2</gadget>
<output>46</output>

<result>46</result>