constant = 1
firstrun = True
def intro():
	print ""
	print "this program will tell you what grade you can"
	print "get on the final and still keep a certian letter grade."
	print ""

def inter():
	print ""
	print "Do you want to calculate your grade again. (y,n)"

def start():
	print ""
	print "What grade do you have in the class"
		
	grade = input( ">" ) # Getting the input of the grade
	grade2 = grade*0.8   # The final is worth 20% of your grade, thus the .8

	# The if else function here will tell you what score you can get on the final and 
	# keep an A in the class. If the result is zero, 
	# then you will get AT LEAST that grade
	print "For an A"	    
	if (89.55-grade2)/20<0:
		print ( "0" )
	else: print (((89.55-grade2)/20)*100)

	print "for a B"
	if (79.55-grade2)/20<0:
		print ( "0" )
	else: print (((79.55-grade2)/20)*100)
		
	print "for a C"
	if (69.55-grade2)/20<0:
		print ( "0" )
	else: print (((69.55-grade2)/20)*100)
		
	print "for a D"
	if (59.55-grade2)/20<0:
		print ( "0" )
	else: print (((59.55-grade2)/20)*100)
	print "NOTE- if there is a 0 or a number over 100 displayed on the grade,"
	print "that means that you can not get that grade"




while constant == 1:
	if firstrun == True:
		intro()
		start()
		firstrun = False # sets the variable to false so it will go to the else on the next run
		inter() 
		# I was having some trouble with the repeting scrips not asking if you wanted
		# to calculate the grade again and would just give you a promp for it. so I added
		# another function that did ask
		
	else:
		answer = raw_input ( ">" ) # dont forget to add a raw_input, it can be very frusterating when you dont.
		if answer == "y":
			start()
			print ""
			print "Do you want to calculate your grade again.(y,n)"
			
		else:
			exit()