Xiaoli and her father and mother go to the hairdresser for a haircut. Xiaoli takes 20 minutes, mother takes 2 hours, and father takes 30 minutes. What is the minimum total waiting time of the three people?
小丽和爸爸、妈妈去美发店理发，小丽要20分钟，妈妈要2小时，爸爸要30分钟，三人等候时间的总和最少要多少分钟．
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">120 * 1</gadget>
<output>120</output>

<gadget id="calculator">60 + 60 + 120</gadget>
<output>240</output>

<result>240</result>