What was the change in operating profit under Networks & Security?
{"Networks & Security": {"2019": 73.9, "2018": 56.4}, "Lifecycle Service Assurance": {"2019": 18.1, "2018": 17.4}, "Connected Devices": {"2019": 9.5, "2018": 10.5}, "Corporate": {"2019": -8.6, "2018": -7.2}, "Adjusted operating profit1": {"2019": 92.9, "2018": 77.1}, "Exceptional items": {"2019": 0.5, "2018": -13.1}, "Acquisition related costs": {"2019": -0.1, "2018": "\u2013"}, "Acquired intangible asset amortisation": {"2019": -1.2, "2018": -3.7}, "Share-based payment": {"2019": -3.5, "2018": -2.8}, "Reported operating profit": {"2019": 88.6, "2018": 57.5}}
networks_security_2019 = df["Networks & Security"]["2019"]
networks_security_2018 = df["Networks & Security"]["2018"]
answer = networks_security_2019 - networks_security_2018