At a certain bus departure station, bus No. 1 departs every 4 minutes, bus No. 2 departs every 5 minutes, and bus No. 3 departs every 7 minutes. After these three buses depart at the same time, how many more minutes will it take to depart at the same time?
某公共汽车始发站，1路车每4分发车一次，2路车每5分发车一次，3路车每7分发车一次，这三路汽车同时发车后，至少再经过多少分同时发车？
<gadget id="calculator">4 * 5 * 7</gadget>
<output>140</output>

<result>140</result>