<P> A recommendation for admission from the Security Council requires affirmative votes from at least nine of the council's fifteen members, with none of the five permanent members using their veto power . The Security Council's recommendation must then be approved in the General Assembly by a two - thirds majority vote . </P> <P> In principle, only sovereign states can become UN members, and currently all UN members are sovereign states . Although five members were not sovereign when they joined the UN, all subsequently became fully independent between 1946 and 1991 . Because a state can only be admitted to membership in the UN by the approval of the Security Council and the General Assembly, a number of states that are considered sovereign according to the Montevideo Convention are not members of the UN . This is because the UN does not consider them to possess sovereignty, mainly due to the lack of international recognition or due to opposition from one of the permanent members . </P> <P> In addition to the member states, the UN also invites non-member states to become observers at the UN General Assembly (currently two: the Holy See and Palestine), allowing them to participate and speak in General Assembly meetings, but not vote . Observers are generally intergovernmental organizations and international organizations and entities whose statehood or sovereignty is not precisely defined . </P> <P> The UN officially came into existence on 24 October 1945, after ratification of the United Nations Charter by the five permanent members of the United Nations Security Council (the Republic of China, France, the Soviet Union, the United Kingdom, and the United States) and a majority of the other signatories . A total of 51 original members (or founding members) joined that year; 50 of them signed the Charter at the United Nations Conference on International Organization in San Francisco on 26 June 1945, while Poland, which was not represented at the conference, signed it on 15 October 1945 . </P>

Which country is not a member of united nation