Three cargo ships arrive at a certain port at the same time, and they can only unload their cargo one by one. It takes 8 hours to unload No. 1 ship, 4 hours to unload No. 2 ship, and 1 hour to unload No. 3 ship. The sum of the waiting time is the least, what order should be unloaded? And find the sum of the waiting time of the three cargo ships.
三艘货船同时到达某港口，只能一船一船地卸货，1号船卸完需要8小时，2号船卸完需要4小时，3号船卸完需要1小时，要使三艘货船的等候时间的总和最少，应该按怎样的顺序卸货？并求出三艘货船等候的时间总和．
<gadget id="calculator">1 * 3</gadget>
<output>3</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">3 + 8 + 8</gadget>
<output>19</output>

<result>19</result>