What is the total revenue earned from 2018 to 2019?
{"Cloud and related solutions": {"2019": 896164, "2018": 766377}, "Software and services": {"2019": 52364, "2018": 58101}, "Maintenance": {"2019": 48282, "2018": 50581}, "Total revenues": {"2019": 996810, "2018": 875059}}
total_revenue_2018 = df["Total revenues"]["2018"]
total_revenue_2019 = df["Total revenues"]["2019"]
answer = total_revenue_2018 + total_revenue_2019