Beginning from the early 1920s composers of both contemporary and popular music wrote for the musical saw. Probably the first was Dmitri Shostakovich.  He included the musical saw, e.g., in the film music for The New Babylon (1929), in The Nose (opera) (1928), and in Lady Macbeth of the Mtsensk District (opera) (1934). Shostakovich and other composers of his time used the term "Flexaton" to mark the musical saw. "Flexaton" just means "to flex a tone"—the saw is flexed to change the pitch. Unfortunately, there exists another instrument called Flexatone, so there has been confusion for a long time. Aram Khachaturian, who knew Shostakovichs music included the musical saw in his Piano Concerto (Khachaturian) (1936) in the second movement. Another composer was the Swiss Arthur Honegger, who included the saw in his opera Antigone (Honegger) in 1924 . The Romanian composer George Enescu used the musical saw at the end of the second act of his opera Œdipe (opera) (1931) to show in an extensive glissando—which begins with the mezzo-soprano and is continued by the saw—the death and ascension of the sphinx killed by Oedipus. The Italian composer Giacinto Scelsi wrote a part for the saw in his quarter-tone piece Quattro pezzi per orchestra (1959). German composer Hans Werner Henze took the saw to characterize the mean hero of his tragical opera Elegy for young lovers (1961). Other composers were Krysztof Penderecki with Fluorescences (1961), De natura sonoris Nr. 2 (1971) and the opera Ubu Rex (1990), Bernd Alois Zimmermann with Stille und Umkehr (1970), George Crumb with Ancient voices of children (1970), John Corigliano with The Mannheim Rocket (2001). Chaya Czernowin used the saw in her opera "PNIMA...Ins Innere" (2000) to represent the character of the grandfather, who is traumatized by the Holocaust. There are Further Leif Segerstam, Hans Zender (orchestration of "5 préludes" by Claude Debussy), Franz Schreker (opera Christophorus) and Oscar Strasnoy (opera Le bal). Russian composer Lera Auerbach wrote for the saw in her ballet The Little Mermaid (2005), in her symphonic poem Dreams and Whispers of Poseidon (2005), in her oratorio "Requiem Dresden – Ode to Peace" (2012), in her Piano Concerto No.1 (2015), in her comic oratorio The Infant Minstrel and His Peculiar Menagerie (2016) and in her violin concerto Nr.4 "NyX – Fractured dreams" (2017).
Question: How many films did Dmitri Shostakovich include the musical saw in?
Answer: 3