What is the change in Total prepaid expenses between fiscal years 2019 and 2018?
{"October 31, -- ": {"2019": 2019, "2018": 2018}, "(In thousands) -- Parts and supplies": {"2019": 33617, "2018": 28287}, "(In thousands) -- Prepaid insurance": {"2019": 8859, "2018": 8232}, "(In thousands) -- Other prepaid expenses": {"2019": 14455, "2018": 6721}, "(In thousands) -- Total prepaid expenses": {"2019": 56931, "2018": 43240}}
total_prepaid_expenses_2019 = df["(In thousands) -- Total prepaid expenses"]["2019"]
total_prepaid_expenses_2018 = df["(In thousands) -- Total prepaid expenses"]["2018"]
answer = total_prepaid_expenses_2019 - total_prepaid_expenses_2018