 Complete the following phrase:  Upon graduating from the Military Academy in Vilnius, Ladiga served in the Imperial Russian army during World War I and earned the rank of captain. He returned to Lithuania in 1918 and volunteered to the newly formed Lithuanian army. He was appointed as the commander of one of the battalions of the 1st Infantry Regiment. Ladiga quickly rose through the ranks and commanded the Vilkmergė Group in the LithuanianSoviet War. He also led units against the Bermontians and in the PolishLithuanian War. After an unsuccessful campaign in September 1920, Ladiga resigned field office and joined the General Staff in Kaunas. After the 