The General Assembly is the main organ of the United Nations. It is composed of representatives of all Member States, each of which has one vote. Decisions on important questions, such as those on peace and security, admission of new Members and budgetary matters, require a two-thirds majority. Decisions on other questions are reached by a simple majority. The General Assembly's regular session usually begins each year in September. At the start of each regular session, the Assembly elects a new president, 21 Vice-Presidents and the Chairpersons of the Assembly's six Main Committees. In addition to its regular sessions, the Assembly may meet in special sessions at the request of the Security Council, of a majority of Member States, or of one Member if the majority of Members concurs. The Security Council has primary responsibility for the maintenance of international peace and security. When a complaint concerning a threat to peace is brought before it, the Council's first action is usually to recommend to the parties to try to reach agreement by peaceful means. In some cases, the Council itself undertakes investigation and mediation. When a dispute leads to fighting, the Council's first concern is to bring it to an end as soon as possible. On many occasions, the Council has issued cease-fire directives. It also sends United Nations peace-keeping forces to help reduce tensions in troubled areas, keep opposing forces apart and create conditions of calm. The Council may decide on enforcement measures, economic sanctions (such as trade embargoes) or collective military action. The Secretariat carries out the diverse day-to-day work of the Organization. It services the other principal organs of the United Nations and administers the programs and policies laid down by them. At its head is the Secretary-General, who is appointed by the General Assembly on the recommendation of the Security Council for a fiveyear, renewable term.