Lan Lan went to bed at 20:00, and got up on time at 6:00 the next day. How many hours did she sleep in total?
岚岚20：00上床睡觉，第二天6：00准时起床，她一共睡了多少小时．
<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<result>10</result>