text: aux=n=0
  med=0.00
  while True:
      nota=float(input())
      if nota>10 or nota<0:print("nota invalida")
      else:
          aux+=1
          med+=nota
          if aux==2:
              print("media = %.2f"%(med/2))
              while True:
                  print("novo calculo (1-sim 2-nao)")
                  n=int(input())
                  if n==1:
                      aux=n=0
                      med=0.00
                      break
                  elif n==2:
                      break
      if n==2:break
  