What is the change in audit fees between 2018 and 2019?
{"Audit fees (1)": {"2019 ($)": 1196000, "2018 ($)": 1257000}, "Audit-related fees (2)": {"2019 ($)": 0, "2018 ($)": 15000}, "Tax fees (3)": {"2019 ($)": 0, "2018 ($)": 0}, "All other fees (4)": {"2019 ($)": 2000, "2018 ($)": 2000}, "Total": {"2019 ($)": 1198000, "2018 ($)": 1274000}}
audit_fees_1_2018_dollars = df["Audit fees (1)"]["2018 ($)"]
audit_fees_1_2019_dollars = df["Audit fees (1)"]["2019 ($)"]
answer = audit_fees_1_2018_dollars - audit_fees_1_2019_dollars