Task: Question Answering
Input (English): Passage: In 1919 Monteux was appointed chief conductor of the Boston Symphony Orchestra. The orchestra was going through difficult times; its conductor, Karl Muck, had been forced by anti-German agitation to step down in 1917. Sir Henry Wood turned down the post, and despite press speculation neither Sergei Rachmaninoff nor Arturo Toscanini was appointed. At least twenty-four players of German heritage had been forced out with Muck, and orchestral morale was low. Shortly before Monteux took up the conductorship the autocratic founder and proprietor of the orchestra, Henry Lee Higginson, died. He had steadfastly resisted unionisation, and after his death a substantial minority of the players resumed the struggle for union recognition. More than thirty players, including two important principals, resigned over the matter. Monteux set about rebuilding the orchestra, auditioning players from all kinds of musical background, some of whom had not played symphonic music before. By the end of his first season he had restored the orchestra to something approaching its normal complement. He trained the orchestra to a high standard; according to the critic Neville Cardus, Monteux's musicianship "made the Boston Symphony Orchestra the most refined and musical in the world."Monteux regularly introduced new compositions in Boston, often works by American, English and French composers.  He was proud of the number of novelties presented in his years at Boston, and expressed pleasure that his successors continued the practice. He was dismayed when it was announced that his contract would not be renewed after 1924. The official explanation was that the orchestra's policy had always been to appoint conductors for no more than five years. It is unclear whether that was genuinely the reason. One suggested possibility is that the conductor chosen to replace him, Serge Koussevitzky, was thought more charismatic, with greater box-office appeal. Another is that the primmer members of Boston society disapproved of Monteux's morals: he and his second wife had gradually drifted apart and by 1924 he was living with Doris Hodgkins, an American divorcée, and her two children. They were unable to marry until 1928, when Germaine Monteux finally agreed to a divorce. 
Question: What is the full name of the person that replaced Monteux as chief conductor?
Output (English): Serge Koussevitzky.