What was the change in the beginning balance between 2018 and 2019?
{"Beginning balance": {"2019": 3016, "2018": 2071, "2017": "$\u2014"}, "Initial obligation from transfer of Charged-Off Receivables(1)": {"2019": 2705, "2018": 2461, "2017": 2379}, "Fair value changes recognized in other gains (losses), net(2)": {"2019": -1925, "2018": -1516, "2017": -308}, "Ending balance": {"2019": 3796, "2018": 3016, "2017": 2071}}
beginning_balance_2019 = df["Beginning balance"]["2019"]
beginning_balance_2018 = df["Beginning balance"]["2018"]
answer = beginning_balance_2019 - beginning_balance_2018