exercise 3.3.py

try:
	score = raw_input("Your score: ")
	score = float(score)
	if score > 1.0:
		print "Bad score"
	elif score >= 0.9:
		print "A"
	elif score >= 0.8:
		print "B"
	elif score >= 0.7:
		print "C"
	elif score >= 0.6:
		print "D"
	elif score < 0.6:
		print "F"
except: 
	print "Bad score"