What was the change in net cash provided by investing activities from 2018 to 2019?
{"Net cash used in operating activities": {"December 29, 2019": -270413, "December 30, 2018": -543389, "December 31, 2017": -267412}, "Net cash provided by (used in) investing activities": {"December 29, 2019": 21366, "December 30, 2018": 274900, "December 31, 2017": -293084}, "Net cash provided by financing activities": {"December 29, 2019": 344314, "December 30, 2018": 85847, "December 31, 2017": 589932}}
net_cash_2019 = df["Net cash provided by (used in) investing activities"]["December 29, 2019"]
net_cash_2018 = df["Net cash provided by (used in) investing activities"]["December 30, 2018"]
answer = net_cash_2019 - net_cash_2018