What is the change in the Total long-term equity investments from 2018 to 2019?
{"Equity method investments (1)": {"Number of Investees at December 31, 2019": 5, "Original Cost": 7407, "December 31, 2019": 11332, "December 31, 2018": 10667}, "Cost less impairment": {"Number of Investees at December 31, 2019": 9, "Original Cost": 43874, "December 31, 2019": 32462, "December 31, 2018": 25923}, "Total long-term equity investments": {"Number of Investees at December 31, 2019": 14, "Original Cost": 51281, "December 31, 2019": 43794, "December 31, 2018": 36590}}
total_longterm_equity_investments_2019 = df["Total long-term equity investments"]["December 31, 2019"]
total_longterm_equity_investments_2018 = df["Total long-term equity investments"]["December 31, 2018"]
answer = total_longterm_equity_investments_2019 - total_longterm_equity_investments_2018