There are 6 taxis parked at a taxi parking lot. After the first taxi leaves, a taxi leaves every 4 minutes. After the first taxi leaves, 2 minutes later, a taxi enters the station. After that, there will be a taxi returning to the station every 6 minutes, and the taxis returning to the station will leave one every 4 minutes after the original taxis leave in turn. Question: After the first taxi leaves, how long does it take for the station to fail to leave on time?
某出租汽车停车站已停有6辆出租汽车，第一辆出租车出发后，每隔4分钟就有一辆出租汽车开出，在第一辆汽车开出2分钟后，有一辆出租汽车进站，以后每隔6分钟就有一辆出租汽车回站，回站的出租汽车，在原有的出租汽车依次开出之后又依次每隔4分钟开出一辆．问：第一辆出租汽车开出后，经过最少多少时间车站不能正点发车？
<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<gadget id="calculator">24 - 2</gadget>
<output>22</output>

<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<gadget id="calculator">11 + 6</gadget>
<output>17</output>

<gadget id="calculator">4 * 17</gadget>
<output>68</output>

<gadget id="calculator">68 + 4</gadget>
<output>72</output>

<result>72</result>