TIME(BC/\AD)

beginning = input("When did the World begin? ")
if beginning = "4000.BC":
       present_year = -4000 + 2017\
       print("The present year is", present_year)
elif  beginning = "on the first day"
        actual_year = 4000 + 2017
        print("The present year is", actual_year)
else:
        print("Your answer is", beginning,"\n",
                  "try again!")