The United States is divided into 50 states, which comprise the federal entities. Under the 10th Amendment to the U.S. Constitution, all governmental powers not granted to the Federal government of the United States nor prohibited by it to the States, are reserved to the States respectively, making the United States a decentralised federation. However, State law is trumped by Federal law when the two may come into contact. U.S. states all share a similar system of government to the national level with a directly elected and usually quite powerful executive styled Governor and a state legislature exercising legislative authority. In 49 states out of 50 as well as three of the inhabited Territories of the United States (Puerto Rico, Northern Mariana Islands, and American Samoa), the legislature is bicameral with the houses commonly, though not exclusively being styled House of Representatives and Senate although the name of the legislative body as a whole varies between the states (the most common are General Assembly (Itself sometimes a term for the lower house of a state legislature) such as in North Carolina or simply Legislature as in Texas). In Nebraska, United States Virgin Islands and Guam (the latter two being federal territories rather than states) the legislature is unicameral.