How much more revenue does the company have in Asia have over Europe for 2019?
{"Europe": {"175.9": 165.6, "21.5%": 20.2, "339.5": 126.2, "26.4%": 9.8}, "Asia": {"175.9": 476.6, "21.5%": 58.3, "339.5": 818.2, "26.4%": 63.7}, "": {"175.9": 818.1, "21.5%": 100.0, "339.5": 1283.9, "26.4%": 100.0}}
asia_revenue_2019 = df["Asia"]["339.5"]
europe_revenue_2019 = df["Europe"]["339.5"]
answer = asia_revenue_2019 - europe_revenue_2019