What is the sum of the total amount of goodwill for 2017 and 2018?
{"": {"Business": "", "Consumer": "(Dollars in millions)", "Total": ""}, "As of December 31, 2017(1)": {"Business": 20197, "Consumer": 10278, "Total": 30475}, "Purchase accounting and other adjustments(2)(3)": {"Business": 250, "Consumer": 32, "Total": 282}, "Impairment": {"Business": "\u2014", "Consumer": -2726, "Total": -2726}, "As of December 31, 2018": {"Business": 20447, "Consumer": 7584, "Total": 28031}}
total_2017 = df["As of December 31, 2017(1)"]["Total"]
total_2018 = df["As of December 31, 2018"]["Total"]
answer = total_2017 + total_2018