Question: Vladimir Yaroshenko was a soloist with the choreographer who dominated Russian ballet for how many years?
Context: Igor Dmitrievich Belsky (Russian: Игорь Дмитриевич Бельский ; 28 March 1925, Saint Petersburg, Russia – 3 July 1999, Saint Petersburg) was a Russian ballet dancer and choreographer.  After 20 years of solo work (1942–62) he became a chief choreographer of Maly Theatre (1962–73), artistic director of Kirov Ballet (1973–77), artistic director of Cairo Ballet (1977–78), chief ballet master at the Leningrad Music Hall (1979–92), and artistic director of the Vaganova Academy of Russian Ballet. Askold Anatolievich Makarov (Russian: Аско́льд Анато́льевич Мака́ров ; 3 May 1925 – 25 December 2000) was a Russian ballet dancer and ballet professor, leading soloist at the Kirov Ballet during the 1960s and early 1970s.  Director of the Saint-Petesburg State Academic Ballet from 1976 to 2000.  Awarded with: State Prize of the USSR (1951) and People's Artist of the USSR (1983). Valery Vorona (Russian: "Валерий Ворона" ) is a Russian violinist, soloist, conductor, and Meritorious Artist.  Vorona graduated from the Gnessin State Musical College and was a post-graduate student at the Moscow Conservatory where he later became a professor.  Later on he became a conductor and teacher in positions which added to his career.  Currently he is both artistic director and conductor-in-chief of the Moscow Chamber Orchestra for young violinists as well as a soloist of the Moscow Philharmonic Orchestra and a President of the Russian Performing Art Foundation.  He also serves as a rector at the Ippolitov-Ivanov Mupic Pedagogical Institute and by 2008 became both conductor and soloist of the Saint Petersburg International Economic Forum.  He has participated at various festivals such as the Russian Festival in San Francisco as well as "Vladimir Spivakov Festival" and Sakharov Festival in Nizhny Novgorod.  Besides national performances he has also performed overseas in such countries as France, Greece, Israel, Italy, Spain, the United States and various former Soviet republics.  He has appeared with many well-known conductors including Ukrainian Oleh Krysa and Oleksandr Bondurianskyi and the Russian conductors Valentin Berlinsky, Vladimir Ponkin, Vladimir Repin, Yuri Bashmet, and Maxim Vengerov. Avdotia Timofeyeva (1739-?) , was a Russian ballerina.  She belonged to the first group of ballet dancers in the history of Russian ballet.  Timofejeva was a part of the first group of ballet students trained by the founder of the Russian ballet, Jean-Baptiste Landé, and was given a position in the ballet of the Imperial theatres in 1748.  She performed many parts in the ballets by Giovanni Battista Locatelli and Antonio Sacco. Yury Nikolayevich Grigorovich (Russian: Ю́рий Никола́евич Григоро́вич ; born 2 January 1927 in Leningrad) is a Soviet and Russian dancer and choreographer who dominated the Russian ballet for 30 years. Vladimir Viktorovich Vasiliev (Russian: Влади́мир Ви́кторович Васи́льев), born 18 April 1940 in Moscow, Russia, is a Russian ballet dancer and choreographer.  He was a principal dancer with the Bolshoi Ballet and its director from 1995 to 2000. Valery Kritskov is a Russian conductor who used to take conducting lessons at the Moscow Institute of Culture which were taught by Kirill Tikhonov.  He graduated from there in 1988 and then worked in Moscow-based Helikon Opera till he got employed with Novaya Opera in 2002.  While there, he conducted many operas including Nikolai Rimsky-Korsakov's "The Snow Maiden" and "The Tsar’s Bride" as well as Anton Rubinstein's "The Demon" and Tchaikovsky's "The Maid of Orleans".  He also conducted works by the Italian composers such as Pietro Mascagni's "Cavalleria rusticana" and Ruggero Leoncavallo's "Pagliacci" and German such as Richard Wagner's "Lohengrin" and Strauss' "Die Fledermaus" as well as a concert dedicated to Vincenzo Bellini.  Besides operas, he is also known for his conducting of the Russian ballet based on works by Tchaikovsky and Sergei Prokofiev as well as German and Austrian ballet composers such as Ludwig Minkus and Charles Gounod.  Later on, he became a conductor of the Coppélia ballet which was based by Léo Delibes work and was produced by Imperial Russian Ballet.  Currently he has two CD recordings called "Chorus of the Novaya Opera Theatre of Moscow" and the "Soloists of the Novaya Opera Theatre of Moscow". Vladimir Yaroshenko (Russian: Владимир Ярошенко; born November 2, 1985 in Slavyansk-na-Kubani) – Polish-Russian ballet dancer, first soloist with Yury Grigorovich’s Ballet Theatre, Krasnodar, trained in classical Russian ballet school.  Polish resident since 2007, engaged with Teatr Wielki, Warsaw, where since September 2010 is a first soloist of Polish National Ballet under direction of Krzysztof Pastor. Andrey Ermakov (Russian: Андрей Андреевич Ермаков ), (born May 27, 1987) is a Russian ballet dancer, a winner of 'Soul of Dance' award (Russian 'Ballet' magazine, 2013), who performs as a soloist with the Mariinsky Ballet (formerly the Kirov Ballet). Marius Ivanovich Petipa (Russian: Ма́риус Ива́нович Петипа́), born Victor Marius Alphonse Petipa (11 March 181814 July [O.S. 1 July] 1910 ) was a French and Russian ballet dancer, pedagogue and choreographer.  Petipa is considered to be the most influential ballet master and choreographer in ballet history.
Answer: 30