Xiao Ming participated in the summer camp from July 12th to August 3rd. How many days did he go there?
小明7月12日至8月3日参加了夏令营活动，一共去了多少天．
<gadget id="calculator">31 - 12</gadget>
<output>19</output>

<gadget id="calculator">19 + 1</gadget>
<output>20</output>

<gadget id="calculator">20 + 3</gadget>
<output>23</output>

<result>23</result>