class Student:
	"""An ordinary student who may or rather may not get scholarship"""
	def __init__(self, name, degree):
		self.name = name
		self.degree = degree
		self.courses = []
		self.marks = {}
		
	def show(self):
		print self.name + " is studying "+  self.degree

	def addcourse(self, course):
		self.courses.append(course)

	def entermark(self, course, mark):
		self.marks[course] = mark

	def print_marks(self):
		for c in self.marks.keys():
			print c, self.marks[c]


class PHDStudent(Student):
	"""The postgraduate research student who gets stipend no matter what"""
	def __init__(self, name, field):
		Student.__init__(self, name, "")
		self.field = field
		del self.degree
		del self.courses
		del self.marks
		self.publications = []
	
	def show(self):
		print self.name, "is doing research in", self.field

	def publish_paper(title):
		self.publications.append(title)

	def publist():
		for p in publications:
			print p

#to run the module 
if __name__ == "__main__":
	name = input("enter the undegraduate's name (don't forget to quote!): ")
	degree = input("enter the undegraduate's degree (don't forget to quote!): ")
	print "Creating the student x"
	x = Student(name,degree)
	name = input("enter the PhD student's name (don't forget to quote!): ")
	degree = input("enter the PhD student's field (don't forget to quote!): ")
	print "Creating the student y"
	y = PHDStudent(name,degree)

	x.show()
	y.show()