The Young Pioneers Brigade of Guangming Elementary School arranges the young pioneers into several groups to prepare for the campfire party. If there are 6 people in each group, there will be 5 people in the end; 5 people in each group, 4 people in the end; 7 people in each group, 6 people in the end; There are 8 people in each group and 7 people in the end. How many young pioneers are there at least in this brigade?
光明小学少先队大队部将少先队员编排成若干个小组，为营火晚会做准备，如果每组6人最后余5人；每组5人，最后余4人；每组7人，最后余6人；每组8人最后余7人．这个大队至少有少先队员多少人？
<gadget id="calculator">5 * 7 * 24</gadget>
<output>840</output>

<gadget id="calculator">840 - 1</gadget>
<output>839</output>

<result>839</result>