The Allied forces were now large, despite the Russian exit from the war due to the Treaty of Brest-Litovsk in March 1918. Greece and its army (nine divisions) were fully committed to the Entente, while 6,000 Czech and Slovak former prisoners of war held on the Italian front were re-armed, re-organized, and transferred to the Macedonian front to fight for the Entente. The Bulgarians had also increased their army during 1917, and in total manpower, the two sides were roughly equal battalions vs. battalions, plus ten German battalions). However, as 1918 progressed, it was clear that the Entente had momentum the Central Powers lacked. Russian defeat had yielded no meaningful benefit to the Central Powers. The Ottoman Empire faced progressive loss of Arab lands. In Austria-Hungary, non-German and non-Hungarian parts of the multinational empire grew more openly restive. On the Western Front, intense German spring offensives had not defeated France, while American deployment was increasingly effective. Though Bulgaria and the United States were not at war with each other, German victory over the United States appeared conceptually infeasible. Finally, and most importantly for Bulgaria, almost all of its territorial war aims were already achieved, but as World War I was not merely a third Balkan War, Bulgaria could not quit. Alongside its partners, Bulgaria continued to suffer high casualties and civilian privation, including food shortages, seemingly to achieve the unrealized objectives of its allies. As a constitutional monarchy, Bulgaria depended on the consent of its people to keep fighting, while stress and discontent with the war grew.