What is the total fair value of related party 5.5% convertible senior notes due December 15, 2021 in 2018 and 2019?
{"Balance as of December 31, 2019 -- Related party": {"Fair value": 6727, "Carrying value": 8864, "Face value": 10000}, "Balance as of December 31, 2019 -- Others": {"Fair value": 65257, "Carrying value": 84648, "Face value": 97000}, "Balance as of December 31, 2019 -- ": {"Fair value": 71984, "Carrying value": 93512, "Face value": 107000}, "Balance as of December 31, 2018 -- Related party": {"Fair value": 5879, "Carrying value": 8378, "Face value": 10000}, "Balance as of December 31, 2018 -- Others": {"Fair value": 57031, "Carrying value": 79433, "Face value": 97000}, "Balance as of December 31, 2018 -- ": {"Fair value": 62910, "Carrying value": 87811, "Face value": 107000}}
fair_value_2019 = df["Balance as of December 31, 2019 -- Related party"]["Fair value"]
fair_value_2018 = df["Balance as of December 31, 2018 -- Related party"]["Fair value"]
answer = fair_value_2019 + fair_value_2018