What was the difference in the total amortized cost and fair value?
{"Due in one year or less": {"Amortized Cost": 591, "Fair Value": 589}, "Due after one year through five years": {"Amortized Cost": 644, "Fair Value": 642}, "Due after five years through ten years": {"Amortized Cost": 455, "Fair Value": 452}, "": {"Amortized Cost": 1690, "Fair Value": 1683}}
amortized_cost = df[""]["Amortized Cost"]
fair_value = df[""]["Fair Value"]
answer = amortized_cost - fair_value