Three trucks come to the parking lot of a logistics company to unload at the same time, and they can only unload one truck at a time. It takes 1 hour for truck A, 2 hours for truck B, and 3 hours for truck C. The total waiting time of the three trucks is what is the minimum
三辆货车同时来到某物流公司的停车场卸货，只能一车一车的卸货，甲车要1个小时，乙车要2个小时，丙车要3小时，三辆车的等候时间总和最少是多少
<gadget id="calculator">1 * 3</gadget>
<output>3</output>

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

<gadget id="calculator">3 + 4 + 3</gadget>
<output>10</output>

<result>10</result>