What is the change in net cash provided by operating activities from 2018 to 2019?
{"Net income": {"2019": 271885, "2018": 365034}, "Non-cash expenses": {"2019": 180987, "2018": 87906}, "Change in receivables": {"2019": -11777, "2018": 21489}, "Change in deferred revenue": {"2019": 23656, "2018": 1255}, "Change in other assets and liabilities": {"2019": -33623, "2018": -63542}, "Net cash provided by operating activities": {"2019": 431128, "2018": 412142}}
net_cash_2019 = df["Net cash provided by operating activities"]["2019"]
net_cash_2018 = df["Net cash provided by operating activities"]["2018"]
answer = net_cash_2019 - net_cash_2018