# Concept of "CLASS under CLASS"
#Creating another class named"School".


class School:
  def __init__(self):
    self.students = []

  def findTopper(self):
    topper = self.students[0]
    return topper

  def addStudent(self, student):
    self.students.append(student)



class Student:

  def __init__(self, name, marks):  
    self.name = name
    self.marks = marks
    self.grade = ""

  def calculateGrade(self):
    if self.marks <40:
      self.grade = "D"
    elif self.marks <60:
      self.grade = "C"
    elif self.marks <80:
      self.grade = "B"
    else:
      self.grade = "A"  

  def displayGrade(self):
    print(self.name)
    print("Grade - ")
    print(self.grade)


school1 = School()

for i in range(1):
    name = input("Enter Name: ")
    marks = int(input("Enter Marks:"))

    st = Student(name, marks)
    st.calculateGrade()
    school1.addStudent(st)


topper = school1.findTopper()
print("Topper is -")
print(topper.name)