为什么是996？
今天做ECNU 比赛的时候发现有一道题是讲996的。我这才知道了996是怎么来的。
As a programmer, you might know that programmers have a self-invented way to represent their workinghours, namely std, which means, start working at s a.m., end working at t p.m. and working d days a week. You might also know that recently there has been a campaign called 996.ICU which objects to long working hours and demands rights.
作为程序员，你可能知道程序员发明了一种方法来表示他们的工作时间，叫做std表示法，意思是从上午s点开始工作，直到下午t点，一周工作d天。你可能还了解到最近有一个如火如荼的运动叫996.ICU，它就是为了反对长时间工作以及争取合法权益而兴起的。
输入类似std的表达式
国家实行劳动者每日工作时间不超过八小时、平均每周工作时间不超过四十四小时的工时制度。
