What is the change in net increase in cash and cash equivalents for year ended 2018 and 2019 ?
{"Cash, cash equivalents and marketable securities (end of period)": {"2019": 2455194, "2018": 1969670}, "Net cash provided by (used in): -- Operating activities": {"2019": 70615, "2018": 9324}, "Net cash provided by (used in): -- Investing activities": {"2019": -569475, "2018": -810633}, "Net cash provided by (used in): -- Financing activities": {"2019": 736351, "2018": 1072182}, "Net cash provided by (used in): -- Effect of foreign exchange on cash and cash equivalents": {"2019": 1742, "2018": -1867}, "Net cash provided by (used in): -- Net increase in cash and cash equivalents": {"2019": 239233, "2018": 269006}, "Net cash provided by (used in): -- Change in marketable securities": {"2019": 246291, "2018": 762625}, "Net cash provided by (used in): -- Net increase in cash, cash equivalents and marketable securities": {"2019": 485524, "2018": 1031631}}
net_increase_2019 = df["Net cash provided by (used in): -- Net increase in cash and cash equivalents"]["2019"]
net_increase_2018 = df["Net cash provided by (used in): -- Net increase in cash and cash equivalents"]["2018"]
answer = net_increase_2019 - net_increase_2018