The London Olympic Games opened on July 27, 2012 local time and closed on August 12, how many days did it last?
伦敦奥动会于当地时间2012年7月27日开幕，8月12日闭幕，历时多少天．
<gadget id="calculator">31 - 27</gadget>
<output>4</output>

<gadget id="calculator">4 + 1 + 12</gadget>
<output>17</output>

<result>17</result>