Xiao Gang, Xiao Ming and Xiao Juan took 2, 3 and 1 thermos bottles to fetch water together, but there was only one hot water faucet. May I ask how to arrange the order of their fetching water so that the total time (including waiting time) spent by them fetching water is the least? (Assume that it takes 1 minute to fill a bottle of water, and there is no gap in the middle)
小刚、小明和小娟分别拿2个、3个、1个暖水瓶一起去打水，热水笼头只有一个．试问怎样安排他们的打水次序，才使他们打水所花的总时间(包括等候的时间)最少？(假定接满1瓶水需1分钟，中间接水无间隙)
<gadget id="calculator">1 * 3</gadget>
<output>3</output>

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

<gadget id="calculator">3 * 1</gadget>
<output>3</output>

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

<result>10</result>