What was the change in the Beginning balance from 2018 to 2019?
{"Beginning balance": {"2019": 6164, "2018": 4931}, "Additions based on tax positions related to current year": {"2019": 164, "2018": 142}, "Additions for tax positions of prior years": {"2019": 231, "2018": 1444}, "Reductions due to change in foreign exchange rate  ": {"2019": -301, "2018": -353}, "Expiration of statutes of limitation": {"2019": -165, "2018": "\u2014"}, "Reductions due to settlements with tax authorities": {"2019": -77, "2018": "\u2014"}, "Ending balance": {"2019": 6016, "2018": 6164}}
beginning_balance_2019 = df["Beginning balance"]["2019"]
beginning_balance_2018 = df["Beginning balance"]["2018"]
answer = beginning_balance_2019 - beginning_balance_2018