The Italo-Turkish or Turco-Italian War  was fought between the Kingdom of Italy and the Ottoman Empire from September 29, 1911, to October 18, 1912. As a result of this conflict, Italy captured the Ottoman Tripolitania Vilayet , of which the main sub-provinces  were Fezzan, Cyrenaica, and Tripoli itself. These territories together formed what became known as Italian Libya. During the conflict, Italian forces also occupied the Dodecanese islands in the Aegean Sea. Italy had agreed to return the Dodecanese to the Ottoman Empire in the Treaty of Ouchy in 1912  Treaty of Lausanne). However, the vagueness of the text allowed a provisional Italian administration of the islands, and Turkey eventually renounced all claims on these islands in Article 15 of the 1923 Treaty of Lausanne. Although minor, the war was a significant precursor of the First World War as it sparked nationalism in the Balkan states. Seeing how easily the Italians had defeated the weakened Ottomans, the members of the Balkan League attacked the Ottoman Empire starting the First Balkan War before the war with Italy had ended. The Italo-Turkish War saw numerous technological changes, notably the airplane. On October 23, 1911, an Italian pilot, Captain Carlo Piazza, flew over Turkish lines on the world's first aerial reconnaissance mission, and on November 1, the first ever aerial bomb was dropped by Sottotenente Giulio Gavotti, on Turkish troops in Libya, from an early model of Etrich Taube aircraft. The Turks, lacking anti-aircraft weapons, were the first to shoot down an aeroplane by rifle fire.
Question: How many main sub-provinces were there of the Ottoman Tripolitania Vilayet?
Answer: 3