Thailand is a country located in Southeastern Asia bordering the Andaman Sea and the Gulf of Thailand. Neighboring countries include Burma, Cambodia, Laos, and Malaysia. The geography consists of a mountain range in the west and a southern isthmus that joins the landmass with Malaysia. The government system is a constitutional monarchy; the chief of state is the king, and the head of government is the prime minister. Thailand has a mixed economic system in which there is a variety of private freedom, combined with centralized economic planning and government regulation. Thailand is a member of the Asia-Pacific Economic Cooperation (APEC) and the Association of Southeast Asian Nations (ASEAN).