What was the total Adjusted EBITDA for Telematics Systems and Software & Subscription Services in 2017?
{"Segment -- Telematics Systems": {"2018": 48943.0, "2017": 47432.0, "$ Change": 1511.0, "% Change": 3.2}, "Segment -- Software & Subscription Services": {"2018": 8233.0, "2017": 3075.0, "$ Change": 5158.0, "% Change": 167.7}, "Segment -- Satellite": {"2018": "-", "2017": 2447, "$ Change": -2447, "% Change": -100.0}, "Segment -- Corporate Expense": {"2018": -4794.0, "2017": -3586.0, "$ Change": -1208.0, "% Change": 33.7}, "Segment -- Total Adjusted EBITDA": {"2018": 52382.0, "2017": 49368.0, "$ Change": 3014.0, "% Change": 6.1}}
total_telematics = df["Segment -- Telematics Systems"]["2017"]
total_software = df["Segment -- Software & Subscription Services"]["2017"]
answer = total_telematics + total_software