def grader(marks):
if marks > 100 and marks < 0:
return "Input Marks between zero and hundred"
elif marks <=60:
return "F"
elif marks <=70:
return "D"
elif marks <=80:
return "C"
elif marks <= 90:
return "B"
elif marks <= 100:
return "A"
else:
return "Wrong Marks"
# taking input into marks variable
marks = int(input("Enter Marks: \n"))
grade = grader(marks)
print(grade)