4 people make copies, Xiao Ming makes copies for 2 minutes, function copies for 3 minutes, a copy for 5 minutes, Sun Yan makes copies for 1 minute, how long should the four people wait at least?
4个人复印，小明复印2分钟，功能复印3分钟，一本复印5分钟，孙彦复印1分钟，四个人最少需要等待多少时间？
<gadget id="calculator">1 * 4</gadget>
<output>4</output>

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

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

<gadget id="calculator">4 + 6 + 6 + 5</gadget>
<output>21</output>

<result>21</result>