Zambia is a landlocked country located in Southern Africa. Neighboring countries include Angola, the Democratic Republic of the Congo, Malawi, Mozambique, Namibia, Tanzania, and Zimbabwe. The geography of Zambia is mostly high plateau with some mountains. The government system is a republic; the chief of state and head of government is the president. Zambia has a mixed economy in which there is a variety of private freedom, combined with centralized economic planning and government regulation. Zambia is a member of the Common Market for Eastern and Southern Africa (COMESA) and the Southern African Development Community (SADC).