popular initiative; and the approval or amendment of the nation's budget proposed by the prime minister. The Congress of Deputies The Congress of Deputies must be integrated by a minimum of 300 and a maximum of 400 deputies (members of parliament) – currently 350 – elected by universal, free, equal, direct and secret suffrage, to four-year terms or until the dissolution of the Cortes Generales. The voting system used is that of proportional representation with closed party lists following D'Hondt method in which the province forms a constituency or electoral circumscription and must be assigned a minimum of 2 deputies; the autonomous cities of Ceuta and Melilla, are each assigned one deputy. The Congress of Deputies can initiate legislation, and they also have the power to ratify or reject the decree laws adopted by the executive. They also elect, via a vote of investiture, the prime minister (the "president of the Government"), before being formally sworn to office by the King. The Congress of Deputies may adopt a motion of censure whereby it can vote out the prime minister by absolute majority. On the other hand, the prime minister may request at any time a vote of confidence from the Congress of Deputies. If the prime minister fails to obtain it, then the Cortes Generales are dissolved, and new elections are called. Senate The upper chamber is the Senate. It is nominally the chamber of territorial representation. Four senators are elected for each province, with the exception of the insular provinces, in which the number of senator varies: three senators are elected for each of the three major islands – Gran Canaria, Mallorca and Tenerife – and one senator for Ibiza-Formentera, Menorca, Fuerteventura, La Gomera, El Hierro, Lanzarote and La Palma. The autonomous cities of Ceuta and Melilla each elect two senators. In addition, the legislative assembly of each autonomous community designates one senator, and another for each one million inhabitants. This designation must follow proportional representation. For the 2011 elections, this system allowed for 266 senators, 208 of which were elected and 58 of which were designated by the autonomous communities. Senators serve for four-year terms or until the dissolution of the Cortes Generales. Even though the constitution explicitly refers to the Senate as the chamber of territorial representation, as seen from the numbers before, only one-fifth of the senators actually represent the autonomous communities. Since the constitution allowed