The second grade students participated in two summer camps in Hangzhou Paradise and Qiandao Lake. 36 people participated in Hangzhou Amusement Park, 28 people participated in Qiandao Lake, and 8 people participated in both summer camps. How many people in the second grade participated in the summer camp activities?
二年级同学参加杭州乐园和千岛湖两个夏令营活动．参加杭州乐园的有36人，参加千岛湖的有28人，两个夏令营都参加的有8人．二年级一共有多少人参加了夏令营活动．
<gadget id="calculator">28 - 8</gadget>
<output>20</output>

<gadget id="calculator">36 + 20</gadget>
<output>56</output>

<result>56</result>