What was the change in Foreign income between 2018 and 2019?
{"Domestic": {"January 31, 2020": 895, "February 1, 2019": 680, "February 2, 2018": 462}, "Foreign": {"January 31, 2020": 543, "February 1, 2019": 1149, "February 2, 2018": 1115}, "Total income before income tax": {"January 31, 2020": 1438, "February 1, 2019": 1829, "February 2, 2018": 1577}}
foreign_february_1_2019 = df["Foreign"]["February 1, 2019"]
foreign_february_2_2018 = df["Foreign"]["February 2, 2018"]
answer = foreign_february_1_2019 - foreign_february_2_2018