The Democratic Republic of the Congo (DRC) is a country located in Central Africa with a short Atlantic Ocean coastline. Neighboring countries include Angola, Burundi, Central African Republic, Republic of the Congo, Rwanda, South Sudan, Tanzania, Uganda, and Zambia. The geography includes active volcanoes near the city of Goma, mountains in the east, and lowlands around the Congo River that experience seasonal flooding. The government system is a republic; the chief of state is the president, and the head of government is the prime minister. DRC has a mixed economic system which includes a variety of private freedom, combined with centralized economic planning and government regulation. The Democratic Republic of the Congo is a member of the Common Market for Eastern and Southern Africa (COMESA), the Economic Community of Central African States (ECCAS), and the Southern African Development Community (SADC).