Meanwhile, new nations liberated from German rule viewed the treaty as recognition of wrongs committed against small nations by much larger aggressive neighbours. The Peace Conference required all the defeated powers to pay reparations for all the damage done to civilians. However, owing to economic difficulties and Germany being the only defeated power with an intact economy, the burden fell largely on Germany. Austria-Hungary was partitioned into several successor states, including Austria, Hungary, Czechoslovakia, and Yugoslavia, largely but not entirely along ethnic lines. Transylvania was shifted from Hungary to Greater Romania. The details were contained in the Treaty of Saint-Germain and the Treaty of Trianon. As a result of the Treaty of Trianon, 3.3 million Hungarians came under foreign rule. Although the Hungarians made up 54% of the population of the pre-war Kingdom of Hungary, only 32% of its territory was left to Hungary. Between 1920 and 1924, 354,000 Hungarians fled former Hungarian territories attached to Romania, Czechoslovakia, and Yugoslavia. The Russian Empire, which had withdrawn from the war in 1917 after the October Revolution, lost much of its western frontier as the newly independent nations of Estonia, Finland, Latvia, Lithuania, and Poland were carved from it. Romania took control of Bessarabia in April 1918. The Ottoman Empire disintegrated, with much of its Levant territory awarded to various Allied powers as protectorates. The Turkish core in Anatolia was reorganised as the Republic of Turkey. The Ottoman Empire was to be partitioned by the Treaty of Sèvres of 1920. This treaty was never ratified by the Sultan and was rejected by the Turkish National Movement, leading to the victorious Turkish War of Independence and the much less stringent 1923 Treaty of Lausanne.
Question: Over how many years did 354,000 Hungarians flee former Hungarian territories?
Answer: 4