1118.py

while True:

	limit = 0
	addition = 0

	while limit < 2:

		data = float(input())

		if data >= 0 and data <= 10:

			addition += data
			limit += 1

		else:
			print("nota invalida")

	print("media = %.2f" % (addition / 2))

	while True:

		print("novo calculo (1-sim 2-nao)")

		data2 = int(input())

		if data2 == 1 or data2 == 2:
			break

	if data2 == 2:
			break