class Student:

    def __init__(self,n,m):
        self.name = n
        self.major = m
        self.courses = []

    def add_course(self,c):
        self.courses.append(c)
        
    def __str__(self):
        return self.name + ":" + self.major
    

class Course:

    def __init__(self,n,t):
        self.cno = n
        self.title = t
        self.roster = []

    def add_student(self,s):
        self.roster.append(s)
        
    def __str__(self):
        return self.cno + ":" + self.title

s1 = Student("John","CSC")
s2 = Student("Sally","CSC")
s3 = Student("Alice","MATH")
c1 = Course("1301","CS I")
c2 = Course("1302","CS II")

s1.add_course(c1)
s1.add_course(c2)
s2.add_course(c1)
c1.add_student(s1)
c1.add_student(s2)
c2.add_student(s1)

# print the roster for CSC 1301, the c1 object
for s in c1.roster:
    print(s)

John:CSC
Sally:CSC

students = [s1,s2,s3]

for s in students:
    if c1 in s.courses:
        print(s)

John:CSC
Sally:CSC