score=input("Enter score: ")
s=float(score)
if s<=1.0 and s>=0.0:
	if s>=0.9:
		print('A')
	elif s>=0.8:
		print('B')
	elif s>=0.7:
		print('C')
	elif s>=0.6:
		print('D')
	elif s<0.6:
		print('F')
else: print("Enter score between 0.0 and 1.0")

