What is the difference between the highest and lowest bid price in 2019?
{"2018(1) -- First Quarter (1)": {"High": 2.2, "Low": 1.76}, "2018(1) -- Second Quarter (1)": {"High": 1.76, "Low": 1.76}, "2018(1) -- Third Quarter (1)": {"High": 2.5, "Low": 1.25}, "2018(1) -- Fourth Quarter (1)": {"High": 2.0, "Low": 1.99}, "2019(1) -- First Quarter (1)": {"High": 2.3, "Low": 2.0}, "2019(1) -- Second Quarter (1)": {"High": 2.0, "Low": 1.5}, "2019(1) -- Third Quarter (1)": {"High": 1.5, "Low": 1.4}, "2019(1) -- Fourth Quarter (1)": {"High": 3.8, "Low": 1.4}}
high_2019 = df["2019(1) -- Fourth Quarter (1)"]["High"]
low_2019 = df["2019(1) -- Third Quarter (1)"]["Low"]
answer = high_2019 - low_2019