The government of the City and County of San Francisco utilizes the "strong mayor" form of mayoral/council government, composed of the Mayor, Board of Supervisors, several elected officers, and numerous other entities. It is the only consolidated city-county in California, and one of only thirteen charter counties of California. The fiscal year 2007–08 city and county budget was approximately $6 billion. San Francisco utilizes the "strong mayor" form of mayoral/council government, composed of the mayor, Board of Supervisors, several elected officers, and numerous other entities. San Francisco voters use ranked-choice voting to elect the mayor, supervisors, and other elective officers. The Mayor of San Francisco is the head of the executive branch of the city and county government. The mayor has the responsibility to enforce all city laws, administer and coordinate city departments and intergovernmental activities, set forth policies and agendas to the Board of Supervisors, and prepare and submit the city budget at the end of each fiscal year. The mayor has the powers to either approve or veto bills passed by the San Francisco Board of Supervisors, participate in meetings of the Board of Supervisors and its committees, appoint a replacement to fill vacancies in all city elected offices until elections, appoint a member of the Board as acting mayor in his/her absence, and to direct personnels in the case of emergency. The mayor serves a four-year term and is limited to two successive terms. If the mayor dies or resigns, the President of the Board of Supervisors assumes the office, as Dianne Feinstein did after the assassination of George Moscone in 1978.