If a billboard with a length of 15 meters and a width of 11 meters is to be hung with a circle of neon lights around it, how long does the neon light need to be?
一块长15米，宽11米的广告牌，要在它的四周挂上一圈霓虹灯，霓虹灯需要多长？
<gadget id="calculator">15 + 11</gadget>
<output>26</output>

<gadget id="calculator">26 * 2</gadget>
<output>52</output>

<result>52</result>