A certain parking lot has such regulations: each car parks within 3 hours (including 3 hours), and charges 4 yuan per hour, and the part that exceeds 3 hours is charged 5 yuan per hour. A car parked in this parking lot for 8 hours, how much should I pay for the parking fee?
某停车场收费有这样的规定：每辆车停车在3小时以内(含3小时)，每小时收费4元，超过3小时的部分按每小时5元收费．一辆车在该停车场停了8小时，应交停车费共多少元？
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">12 + 25</gadget>
<output>37</output>

<result>37</result>