A head of state is the highest-ranking position in a sovereign state and is vested with powers to act as the chief public representative of that state. In most countries, the head of state is a natural person, but the position is held by a body of persons in the Federal Council of Switzerland and the Presidency of Bosnia and Herzegovina and, in two other United Nations member states, the position is held by two persons jointly: the Co-Princes of Andorra and the Captains Regent of San Marino. The role and functions of the office of a head of state may range from being purely ceremonial figurehead to one that wields autocratic executive power; as the nature of the position of a head of state is for each state to decide; and although several models or patterns exist, there are many idiosyncrasies in different states which preclude tidy classifications.