class Student:
    # The __init__ method accepts arguments

    def __init__(self, name, age, nationality):
        self.__name = name
        self.__age = age
        self.__nationality = nationality

    def set_name(self, name):
        self.__name = name

    def set_nationality(self, nationality):
        self.__nationality = nationality

    def get_name(self):
        return self.__name

    def get_age(self):
        return self.__age

    def get_nationality(self):
        return self.__nationality


class StudentInt(Student):

    def __init__(self, name, nationality):
        super().__init__(name, nationality)


class StudentIntNK(StudentInt):

    def __init__(self, name, nationality, admission, welcomed):
        super().__init__(name, nationality)
        self.__admission = admission
        self.__welcomed = welcomed

    def set_nationality(self, nationality):
        self.__nationality = "NK"

    def set_welcomed(self):
        self.__welcomed = "Not welcomed"

    def get_welcomed(self):
        return self.__welcomed


student_list = []

def make_list():
    # Create an empty list.

    # Add Student objects to the list.
    n = int(input('How many students you want to add?: '))
    print('Enter data for each student.')
    for count in range(0, n):
        # Get the students data.
        print('Index number ' + str(count) + ':')
        name = input('Enter name: ')
        age = float(input('Enter age: '))
        nationality = input('Enter Nationality: ')
        welcomed = True
        if nationality != 'PL':
            s = Student(name, age, nationality)
            student_list.append(s)
        elif nationality == 'NK':
            student_int_nk = Student.__init__(name, age, nationality, welcomed)
            student_list.append(student_int_nk)
        else:
            student = Student(name, age, nationality)
            student_list.append(student)

    # Return the list.
    return student_list


def display_list(student_list):
    for data in student_list:
        print(data.get_name())
        print(data.get_age())
        print(data.get_nationality())
        print()


# The display_list function accepts a list containing
# Student objects as an argument and displays the
# data stored in each object.

def main():
    # Get a list of Student objects.
    students = make_list()

    # Display the data in the list.
    print('Here is the list of students you entered:')
    display_list(students)


# Call the main function.
if __name__ == '__main__':
    main()