Last year, the school organized a long-distance race in winter, from November 15th to December 18th, how many days in total?
去年学校组织冬季长跑，从11月15日开始到12月18日结束，共长跑多少天？
<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<gadget id="calculator">15 + 1 + 18</gadget>
<output>34</output>

<result>34</result>