Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Problem:Passage: In 1860 Binding moved to Göttingen where he studied history and jurisprudence. After a short stay in Heidelberg, where he won a law prize, he moved back to Göttingen to finish his studies. In 1864 he completed his habilitation paper in Latin about Roman criminal law and lectured in criminal law at Heidelberg University. Two years later he was appointed professor of law of state and criminal law and procedure in Basel, Switzerland. In the same year he married Marie Luise Wirsing and published Das burgundisch-romanische Königreich and Entwurf eines Strafgesetzbuches für den Norddeutschen Bund. At this time he also became friends with Johann Jacob Bernoulli - an archaeologist, Jakob Burckhardt - an art historian, and Friedrich Nietzsche - a philosopher. In August 1867 his first son, Rudolf Georg, was born, followed two years later by his second son. Rudolf G Binding later became a famous writer. Karl Binding and his wife were to have one more son and two daughters. In 1869 his family moved to Freiburg, and Binding volunteered to fight in the Franco-Prussian War. Although his lack of military training meant he was unable to serve as a soldier, he was accepted as an orderly and posted to the front, serving in a field hospital. In 1872 he took on a post at the Reichs University in Straßburg. In the same year he moved to Leipzig University, where he was to continue to work for the next 40 years. From 1879 until to 1900 Binding worked in the district court of Leipzig. After becoming Leipzig University's rector and receiving his emeritus, he moved to Freiburg, where his wife died only a few days later at 71 years old. In 1918, during the First World War, Binding left Germany to lecture German soldiers in Macedonia and Bulgarian intellectuals in Sofia.
 Link Information: none Question: What was the population of Sofia the year that Binding was there to lecture intellectuals?
Solution:
Answer: none