Write a question about the following article: Aleksandr Vasilievich Nazarenko  is a Russian historian who works in the Moscow State University. He heads the project "Russia and Central Europe in the Middle Ages" in the World History Institute of the Russian Academy of Sciences. Having studied at the university to gain doctorates in philology and history, Nazarenko revived the tenet of 19th-century Russian historiography that it is impossible to research early East Slavic history without detailed knowledge of ancient languages. Considered a disciple of Vladimir Pashuto, Nazarenko advocates tighter integration of historiography with the auxiliary disciplines of genealogy, numismatics, and sigillography. This approach allowed him to identify and publish a number of new  sources on the history of Kievan Rus. Nazarenko's major findings were summarized in a monograph International Relations of Ancient Rus . Moskva: Russkiĭ fond sodeĭstviii︠a︡ obrazovanii︠u︡ i nauke, 2009 ISBN 5-91244-009-5 Upon its publication in 2009, the book won Nazarenko the Macarius Award of the Russian Orthodox Church.
How many disciplines does Aleksandr advocate for?