class Classroom:

    def __init__(self, subject, teacher, nstudents, nta = 0, maxstudents = 30):
        self.subject = subject
        self.teacher = teacher
        self.nstudents = nstudents
        self.nta = nta
        self.maxstudents = maxstudents
    def getsubject(self):
        return self.subject
    def getteacher(self):
        return self.teacher
    def getnstudents(self):
        return self.nstudents
    def getnta(self):
        return self.nta
    def getmaxstudents(self):
        return self.maxstudents
    def setmaxstudents(self, maxval):
        self.maxstudents=maxval
    def setta(self, ta):
        self.nta = ta
    def addstudent(self, num):
        'increments the number of students in the class by num up to the max'
        for waiting in range(num):
            self.nstudents = self.nstudents + 1
            if self.nstudents == self.maxstudents:
                break
    def dropstudent(self, num):
        'decrements the number of students in the class by num down to 0'
        for waiting in range(num):
            self.nstudents = self.nstudents -1
            if self.nstudents == 0:
                break