For a parking garage, at least 4.5 yuan is paid for one parking, and 2 hours can be parked, and 0.5 yuan is paid for each additional hour of parking (less than 1 hour is calculated as 1 hour). How much should I pay for a car parked in a garage for 5 hours?
一个停车库，停车一次至少交4.5元，可停车2小时，每多停1小时再交0.5元(不到1小时按1小时计算)．一辆汽车在停车库停了5小时，应缴费多少钱？
<gadget id="calculator">4.5 + 0.5</gadget>
<output>5</output>

<gadget id="calculator">0.5 - 2</gadget>
<output>-1.5</output>

<gadget id="calculator">4.5 + (-1.5)</gadget>
<output>3</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 4.5</gadget>
<output>19.5</output>

<result>19.5</result>