What is the name of the person that taught composition at the Leningrad Conservatory?  Answer the above question based on the context below:  The composer's response to his denunciation was the Fifth Symphony of 1937, which was musically more conservative than his earlier works. Premiered on 21 November 1937 in Leningrad, it was a phenomenal success. The Fifth brought many to tears and welling emotions. Later, Shostakovich's purported memoir, Testimony, stated: "I'll never believe that a man who understood nothing could feel the Fifth Symphony. Of course they understood, they understood what was happening around them and they understood what the Fifth was about."The success put Shostakovich in good standing once again. Music critics and the authorities alike, including those who had earlier accused Shostakovich of formalism, claimed that he had learned from his mistakes and become a true Soviet artist. In a newspaper article published under Shostakovich's name, the Fifth Symphony was characterized as "A Soviet artist's creative response to just criticism." The composer Dmitry Kabalevsky, who had been among those who disassociated themselves from Shostakovich when the Pravda article was published, praised the Fifth Symphony and congratulated Shostakovich for "not having given in to the seductive temptations of his previous 'erroneous' ways."It was also at this time that Shostakovich composed the first of his string quartets. His chamber works allowed him to experiment and express ideas that would have been unacceptable in his more public symphonies. In September 1937 he began to teach composition at the Leningrad Conservatory, which provided some financial security but interfered with his creative work.
The answer to this question is:
Shostakovich