Question: Olga Arefieva was a student of a Russian singer, who was best known for his rendition of what song that was the closing ceremony theme song of the 1980 Summer Olympics?

Context paragraphs:
Gerhard Petritsch: Gerhard Petritsch (born 2 September 1940) is an Austrian former sport shooter who competed in the 1972 Summer Olympics, in the 1976 Summer Olympics, in the 1980 Summer Olympics and in the 1984 Summer Olympics.  He won a bronze medal at the 1980 Summer Olympics.

Olga Arefieva: Olga Arefieva (Arefeva) (born 21 September 1967 in Verkhnyaya Salda) is a Russian singer-songwriter, poet and musician.  She graduated from Gnessin State Musical College (her teacher was Lev Leshchenko), founded band "Kovcheg" ("The Ark"), composed more than 400 songs, issued 15 music albums, and won the literary prize of the magazine "Znamya" for her poems.

List of Olympic venues in equestrian: For the Summer Olympics, there are 53 venues that have or will be used for equestrian.  From 1912 to 1992, the events took place in more than one venue.  Since the 1992 Summer Olympics, the equestrian events have taken place on a single venue in an effort to reduce costs.  During the 1964 to the 1980 Summer Olympics, an equestrian event was the final event before the closing ceremonies of the respective Olympics.  The last equestrian event that took place at the main stadium was at the 1988 Summer Olympics though it was not the final event before the closing ceremonies.  That honor would fall for the end of the men's marathon event.  Stockholm Olympic Stadium is the only equestrian venue to serve host for more than one Summer Olympics, doing so in 1912 and 1956.

Bhutan at the 2016 Summer Olympics: Bhutan, a country in Southern Asia, participated in nine Summer Olympic Games between its debut in the 1984 Summer Olympics in Los Angeles, United States and the 2016 Summer Olympics in Rio de Janeiro, Brazil.  The highest number of Bhutanese athletes participating in a Summer Games is six in both the 1984 Summer Olympics and the 1992 Summer Olympics in Barcelona, Spain.  Bhutan competed at the Rio Summer Games from 5 to 21 August 2016.  No Bhutanese athlete has ever won a medal at the Olympics.  The two athletes who were selected to represent Bhutan at the Rio Games were Karma in the women's individual archery tournament and Kunzang Lenchu in the women's 10 metre air rifle shooting contest.  Along with the two athletes, the Secretary General of Bhutan's Olympic Committee, and two coaches, the country's delegation was led by the heir presumptive to the Bhutan throne Jigyel Ugyen Wangchuck.  Karma was selected as the flag bearer for the opening ceremony while Lenchu held it at the closing ceremony.

Lev Leshchenko: Lev Valerjanovich Leshchenko (Russian: Лев Валерианович Лещенко ; born 1 February 1942), is a Russian singer, who was best known for his rendition of "Den Pobedy" and the 1980 Summer Olympics closing ceremony theme song "Do svidanja, Moskva".

South Korea at the 1984 Summer Olympics: South Korea, as "Korea", competed at the 1984 Summer Olympics in Los Angeles, United States.  The nation returned to the Summer Games after participating in the American-led boycott of the 1980 Summer Olympics.  175 competitors, 116 men and 59 women, took part in 97 events in 19 sports.  At the closing ceremony, a segment of their culture was performed, as the country hosted the next Olympics In Seoul.

2012 Summer Paralympics closing ceremony: The closing ceremony of the 2012 Summer Paralympics, also known as The Festival of the Flame, was held on 9 September at the Olympic Stadium in London.  Kim Gavin (who also directed the closing ceremony of the 2012 Summer Olympics) served as director for the ceremony, while Stephen Daldry served as its executive producer.  The ceremony was themed around festivals and the four seasons, and was set to music performed live by the British rock group Coldplay, also joined by special guest performers such as the British Paraorchestra, Rihanna and Jay-Z.

1980 Summer Olympics closing ceremony: The Closing Ceremony of the 1980 Summer Olympics was held at 19:00 Moscow Time (UTC+3) on 3 August 1980 at the Grand Arena of the Central Lenin Stadium.  It was attended by the Chairman of the Presidium of the Supreme Soviet of the USSR, Leonid Brezhnev.  IOC President Lord Killanin closed the Games for the final time and passed the position on to Juan Antonio Samaranch.

Odysseas Dimitriadis: Odysseas Dimitriadis (July 7, 1908 – April 28, 2005) was a Greek and Soviet classical music conductor.  During his 70-year career, Odysseas had conducted a number of the world's leading orchestras, as well as being a main conductor of Georgia, USSR state orchestra and the Bolshoy Theatre orchestra.  In 1980 he conducted during the opening and closing ceremony of the 1980 Summer Olympics, held in Moscow.  He has received a number of awards and titles, including Ambassador of Hellenism, National Artist of the Soviet Union and Golden Medal of Athens.

Saúl Craviotto: Saúl Craviotto Rivero (born 3 November 1984) is a Spanish sprint canoer who has been racing since the mid-2000s.  He has won four Olympic medals: a gold medal in the K-2 500 m with Carlos Pérez at the 2008 Summer Olympics in Beijing, a silver medal in the K-1 200 m event at the 2012 Summer Olympics in London, a gold medal in the K-2 200 m with Cristian Toro at the 2016 Summer Olympics and a bronze medal in the K-1 200 m at the 2016 Summer Olympics in Rio de Janeiro.  He served as the flag bearer for Spain at the closing ceremony of the 2012 Olympics.

Supporting paragraphs: Olga Arefieva Lev Leshchenko
Answer: Do svidanja, Moskva