What is the change in stock compensation between 2018 and 2019?
{"U.S. net operating loss carryforwards": {"2019": 2894000, "2018": 2627000}, "Stock compensation": {"2019": 784000, "2018": 359000}, "Canadian Provincial income tax losses": {"2019": 29000, "2018": 56000}, "Canadian Provincial scientific investment tax credits": {"2019": -4000, "2018": "-"}, "": {"2019": 3703000, "2018": 3042000}, "Valuation allowance": {"2019": -3703000, "2018": -3042000}, "Net deferred tax assets": {"2019": "-", "2018": "-"}}
stock_compensation_2019 = df["Stock compensation"]["2019"]
stock_compensation_2018 = df["Stock compensation"]["2018"]
answer = stock_compensation_2019 - stock_compensation_2018