What was the change in audit fees?
{"Audit Fees": {"2018 ($)": 5859755, "2019 ($)": 5024093}, "Audit-Related Fees": {"2018 ($)": 137420, "2019 ($)": 3178737}, "Tax Fees": {"2018 ($)": 1440168, "2019 ($)": 2346879}, "All Other Fees": {"2018 ($)": 11200, "2019 ($)": 10955}, "Total": {"2018 ($)": 7448544, "2019 ($)": 10560664}}
audit_fees_2019_dollars = df["Audit Fees"]["2019 ($)"]
audit_fees_2018_dollars = df["Audit Fees"]["2018 ($)"]
answer = audit_fees_2019_dollars - audit_fees_2018_dollars