Three students go to the infirmary to see a doctor, and they spend 2 minutes, 4 minutes, and 3 minutes on seeing a doctor respectively. What is the minimum sum of their waiting time for seeing a doctor?
三个同学去医务室看病，三人看病分别用2分钟，4分钟、和3分钟．他们看病等候时间的总和最少是多少分钟．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<gadget id="calculator">6 + 6 + 4</gadget>
<output>16</output>

<result>16</result>