What is the change in the Unrecognized tax benefit, beginning balance from 2018 to 2019?
{"Unrecognized tax benefit, beginning balance": {"December 28, 2019": 25224, "December 29, 2018": 18296, "December 30, 2017": 17978}, "Additions based on tax positions related to the current year": {"December 28, 2019": 3679, "December 29, 2018": 1677, "December 30, 2017": 694}, "Additions based on tax positions from prior years": {"December 28, 2019": "\u2014", "December 29, 2018": 5332, "December 30, 2017": "\u2014"}, "Reductions for tax positions of prior years": {"December 28, 2019": -5, "December 29, 2018": -7, "December 30, 2017": "\u2014"}, "Reductions due to lapse of the applicable statute of limitations": {"December 28, 2019": -98, "December 29, 2018": -74, "December 30, 2017": -376}, "Unrecognized tax benefit, ending balance": {"December 28, 2019": 28800, "December 29, 2018": 25224, "December 30, 2017": 18296}, "Interest and penalties recognized as a component of Provision (benefit) for income taxes": {"December 28, 2019": 59, "December 29, 2018": 71, "December 30, 2017": 67}, "Interest and penalties accrued at period end": {"December 28, 2019": 212, "December 29, 2018": 230, "December 30, 2017": 218}}
unrecognized_tax_2019 = df["Unrecognized tax benefit, beginning balance"]["December 28, 2019"]
unrecognized_tax_2018 = df["Unrecognized tax benefit, beginning balance"]["December 29, 2018"]
answer = unrecognized_tax_2019 - unrecognized_tax_2018