again = 'y'
while(again == 'y'):
	grade = float(input("Enter the grade: "))

	if (grade >= 90):
	    print('A')
	elif (80 <= grade < 90):
	    print('B')
	elif (70 <= grade < 80):
	    print('C')
	elif (60 <= grade < 70):
	    print('D')
	else:
	    print('F')

	again = input("Enter another grade? (y/n):").lower()
print("DONE.  Thank you for playing!")