Please answer a question about the following article about Frédéric Chopin:

Polish composers of the following generation included virtuosi such as Moritz Moszkowski, but, in the opinion of J. Barrie Jones, his "one worthy successor" among his compatriots was Karol Szymanowski (1882–1937). Edvard Grieg, Antonín Dvořák, Isaac Albéniz, Pyotr Ilyich Tchaikovsky and Sergei Rachmaninoff, among others, are regarded by critics as having been influenced by Chopin's use of national modes and idioms. Alexander Scriabin was devoted to the music of Chopin, and his early published works include nineteen mazurkas, as well as numerous études and preludes; his teacher Nikolai Zverev drilled him in Chopin's works to improve his virtuosity as a performer. In the 20th century, composers who paid homage to (or in some cases parodied) the music of Chopin included George Crumb, Bohuslav Martinů, Darius Milhaud, Igor Stravinsky and Heitor Villa-Lobos.

Who was Alexander Scriabin's teacher?
Nikolai Zverev