June 26th is the International Anti-Drug Day, and the Capital Anti-Drug Membership Association held the first ten-thousand-person walk with the theme of "promoting a healthy life and all people participating in anti-drugs". Due to the heavy rain that day, only 12,000 students participated in the long walk, which was less than the original plan (1/5). How many students originally planned to participate in the long walk?
6月26日是国际禁毒日，首都禁毒会员会首次举办了以"提倡健康人生，全民参与禁毒"为主题的万人长走活动．由于当天下起了大雨，只有12000名学生参加了长走活动，比原计划参加长走的学生少(1/5)．原计划参加长走的学生有多少人？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">12_000 / (4/5)</gadget>
<output>15_000</output>

<result>15_000</result>