The business hours of a certain post office are from 8:00 to 12:00 in the morning and from 2:00 to 6:00 in the afternoon. How many hours is the post office open throughout the day
某邮局的营业时间为上午8：00～12：00，下午2：00～6：00．这个邮局全天的营业时间有多少小时
<gadget id="calculator">4 + 4</gadget>
<output>8</output>

<result>8</result>