Complex sentence: In 1913-1915 he attended the Psychoneurological Institute in St. Petersburg and then he moved to the University of Tomsk in Siberia (1915-1920) to complete his law degree.
Split into simpler sentences: In 1913-1915 he attended the Psychoneurological Institute in Saint Petersburg. In 1915 he transferred to the University of Tomsk in Siberia to complete his law degree.