Xiaofang forms a rectangle with two small sticks with a length of 8 cm and two sticks with a length of 5 cm. What is the perimeter of this rectangle?
小芳用两根长8厘米和两根长5厘米的小棒摆成一个长方形，这个长方形的周长是多少．
<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>