What is the total favourable impact foreign currency translation had on certain of their consolidated financial results? 
{"Net sales": {"2019 vs. 2018": -137.2, "2018 vs. 2017": -43.4}, "Cost of sales": {"2019 vs. 2018": 98.4, "2018 vs. 2017": 31.7}, "Selling, general and administrative expenses": {"2019 vs. 2018": 16.3, "2018 vs. 2017": 1.0}, "Net earnings": {"2019 vs. 2018": -15.7, "2018 vs. 2017": -8.2}, "Non-U.S. GAAP Adjusted EBITDA": {"2019 vs. 2018": -25.3, "2018 vs. 2017": -11.1}}
cost_2019 = df["Cost of sales"]["2019 vs. 2018"]
cost_2018 = df["Cost of sales"]["2018 vs. 2017"]
selling_2019 = df["Selling, general and administrative expenses"]["2019 vs. 2018"]
selling_2018 = df["Selling, general and administrative expenses"]["2018 vs. 2017"]
answer = cost_2019 + cost_2018 + selling_2019 + selling_2018