The charging standard for a parking lot is as follows: within 2 hours (including 2 hours), the fee is 5 yuan; after 2 hours, the fee is 2.5 yuan per hour; if it is less than 1 hour, it is charged as 1 hour. Uncle Li paid a total of 12.5 yuan for parking in this parking lot. Do the math, how many hours can Uncle Li park in this parking lot at most?
一个停车场的收费标准如下：2小时以内(含2小时)收费5元，超过2小时后，每小时收费2.5元，不足1小时的，按1小时计费．李叔叔在这个停车场共缴停车费12.5元．算一算，李叔叔在这个停车场最多停车多少小时？
<gadget id="calculator">12.5 - 5</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 / 2.5</gadget>
<output>3</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<result>5</result>