There is a square fountain with a side length of 5 meters. Xiao Ming walks around the fountain. How far does he go?
有一个边长5米的正方形喷水池，小明沿着喷水池走一圈，他走多远？
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>