Question: Jim Courier and Elena Likhovtseva are both famous athletes in what sport?

full_context: Document 1: Maria Sharapova: Maria Yuryevna Sharapova (Russian: Мари́я Ю́рьевна Шара́пова ; ] ; born April 19, 1987) is a Russian professional tennis player. A United States resident since 1994, Sharapova has competed on the WTA tour since 2001. She has been ranked world No. 1 in singles by the WTA on five separate occasions, for a total of 21 weeks. She is one of ten women, and the only Russian, to hold the career Grand Slam. She is also an Olympic medalist, having earned silver for Russia in women's singles at the 2012 Summer Olympics in London.
Document 2: Marin Čilić: Marin Čilić (; born 28 September 1988) is a Croatian professional tennis player. Over the course of his career, Čilić has won 17 ATP singles titles, including the 2014 US Open. His career-high singles ranking is world No. 5, achieved in September 2017. Čilić first came to international prominence by defeating then-World No. 2 Andy Murray in the fourth round of the 2009 US Open. He followed this by reaching the semifinals of the 2010 Australian Open. Among other achievements, Čilić was runner-up at the 2017 Wimbledon Championships, and was a semifinalist at the 2015 US Open as defending champion. Čilić is currently the youngest active male player to have won a slam. Čilić has reached at least the quarterfinal in all four grand slam tournaments. He has a very powerful serve and very powerful groundstrokes.
Document 3: Yevgeny Kafelnikov: Yevgeny Aleksandrovich Kafelnikov (Russian: Евгений Александрович Кафельников ] ; born 18 February 1974) is a Russian former world No. 1 tennis player. He won two Grand Slam singles titles, the 1996 French Open and the 1999 Australian Open. He also won four Grand Slam doubles titles, being the last man to have won both the men's singles and doubles titles at the same Grand Slam tournament, which he did at the 1996 French Open.
Document 4: Anna Kournikova: Anna Sergeyevna Kournikova (Russian: А́нна Серге́евна Ку́рникова ; ] ; born 7 June 1981) is a Russian former professional tennis player. Her appearance and celebrity status made her one of the best known tennis stars worldwide. At the peak of her fame, fans looking for images of Kournikova made her name one of the most common search strings on Google Search.
Document 5: Roger Federer junior years: Swiss tennis player Roger Federer's main accomplishments as a junior player came at Wimbledon, where, in 1998, he won both the singles tournament over Irakli Labadze, in straight sets, and the doubles with Olivier Rochus, over the team of Michaël Llodra and Andy Ram, also in straight sets. In addition, Federer was a runner-up at the US Open Junior tournament in 1998, losing the final to David Nalbandian. Federer would go on to win four other junior singles tournaments in his career.
Document 6: Janko Tipsarević: Janko Tipsarević (, ] ; born 22 June 1984) is a Serbian professional tennis player. His career-high singles ranking is world No. 8, achieved on 2 April 2012. In his career, he has won four ATP World Tour titles, one ATP doubles title, three Futures, and 15 Challenger titles. Tipsarević also won the 2001 Australian Open Junior title. Tipsarević has achieved two victories over a World No. 1 player, having defeated compatriot Novak Djokovic twice. He also has thirteen victories against other players in the top 10: four wins against Tomáš Berdych, and one each against Fernando González, Mikhail Youzhny, David Ferrer, James Blake, Gaël Monfils, Andy Murray and Juan Mónaco. He holds victories over former World No. 1 players Carlos Moyá, Marat Safin, Lleyton Hewitt, Juan Carlos Ferrero and Andy Roddick. His best results at a Grand Slam have been reaching the quarterfinals at the US Open in 2011 and 2012. He is only the second Serb to reach the final 16 at all four different grand slams.
Document 7: Elena Vesnina: Elena Sergeyevna Vesnina (Russian: Еле́на Серге́евна Веснина́ ] ; born 1 August 1986) is a Russian professional tennis player. Her career-high rankings are world No. 13 in singles and World No. 3 in doubles. Vesnina is a four-time Grand Slam champion in doubles competition, having won the 2013 French Open, 2014 US Open, and 2017 Wimbledon Championship tournaments with Ekaterina Makarova, and the 2016 Australian Open mixed doubles title with Bruno Soares.
Document 8: Juan Carlos Ferrero: Juan Carlos Ferrero Donat (] ; born 12 February 1980) is a retired professional tennis player, and a former world No. 1 player, from Spain. He captured the men's singles title at the 2003 French Open, and in September of that year, became the 21st player to hold the world No. 1 ranking. He was also the runner-up at the 2002 French Open and the 2003 US Open. His nickname is "Mosquito" due to his speed and his slight physical build. Ferrero retired from the game after the 2012 Valencia Open 500.
Document 9: Elena Dementieva: Elena Viacheslavovna Dementieva (Russian: Еле́на Вячесла́вовна Деме́нтьева , ] ; born 15 October 1981) is a retired Russian tennis player. Dementieva won the singles gold medal at the 2008 Olympics in Beijing, having previously won the silver medal at the 2000 Olympics in Sydney. She won 16 WTA singles titles, reached the finals of the 2004 French Open and 2004 US Open and reached seven other Grand Slam semi finals. Dementieva was also part of the Russian team that won the 2005 Fed Cup, won the 2002 WTA Championship doubles with Janette Husárová and was the runner-up in two US Open doubles finals – in 2002 with Husárová and in 2005 with Flavia Pennetta. Dementieva achieved a career-high ranking of World No. 3, which was accomplished on 6 April 2009. She announced her retirement on 29 October 2010, after her final match at the 2010 WTA Tour Championships. Dementieva ended her career ranked World No. 9 and between 2003 and 2010 she only ended one year, in 2007, outside the top 10.
Document 10: Jim Courier: James Spencer Courier Jr. (born August 17, 1970) is an American former World No. 1 professional tennis player. During his career, he won four Grand Slam singles titles, two at the French Open and two at the Australian Open. He holds the record for being the youngest man to have reached the finals of all four Grand Slam singles tournaments, at the age of 22 years and 11 months. He also won five Masters 1000 series titles. Until Novak Djokovic in 2016, Courier was the last man to win both the Australian and French Opens in the same calendar year.
Document 11: Vera Zvonareva: Vera Igorevna Zvonareva (Russian: Ве́ра И́горевна Звонарёва ; ] ; born 7 September 1984) is a Russian professional tennis player. She was introduced to tennis at the age of six and turned professional in 2000. Her career high is world No. 2 by the WTA. Zvonareva has won twelve WTA Tour singles titles and reached the finals of the 2008 WTA Tour Championships, 2010 Wimbledon Championships, and 2010 US Open. She also was a bronze medalist at the 2008 Beijing Olympics. In doubles, she has won four Grand Slam titles. Two of the titles came in women's doubles, the first one at the 2006 US Open, partnering Nathalie Dechy, and the other at the 2012 Australian Open, partnering Svetlana Kuznetsova. Her other two came in mixed doubles, the first at the 2004 US Open, partnering Bob Bryan, and her second at the 2006 Wimbledon Championships, partnering Andy Ram.
Document 12: Elena Bovina: Elena Olegovna Bovina (Елена Олеговна Бовина ) (born 10 March 1983) is a professional tennis player from Russia. She reached her career-high singles ranking of World No. 14 in April 2005. Her best performance at a Grand Slam came when she got to the quarter finals of the 2002 US Open, defeating Clarisa Fernández, Jelena Dokic, Stéphanie Foretz and Francesca Schiavone before losing to Lindsay Davenport.
Document 13: Yevgeny Kafelnikov: Yevgeny Aleksandrovich Kafelnikov (Russian: Евгений Александрович Кафельников ] ; born 18 February 1974) is a Russian former world No. 1 tennis player. He won two Grand Slam singles titles, the 1996 French Open and the 1999 Australian Open. He also won four Grand Slam doubles titles, being the last man to have won both the men's singles and doubles titles at the same Grand Slam tournament, which he did at the 1996 French Open.
Document 14: Elena Likhovtseva: Elena Alexandrovna Likhovtseva (Russian: Елена Александровна Лиховцева ] ; born 8 September 1975) is a Russian former tennis player. She turned professional in January 1992 at the age of 16.
Document 15: Félix Auger-Aliassime: Félix Auger-Aliassime (born August 8, 2000) is a Canadian professional tennis player. He reached a career high ATP singles ranking of No. 161 on September 18, 2017 and a career high ITF junior ranking of No. 2 on June 6, 2016. He is the youngest player ever to qualify and to win a main draw match on the ATP Challenger Tour. With his titles at the Open Sopra Steria de Lyon in June 2017 and the Copa Sevilla in September 2017, he became the seventh youngest player in history (16 years, 10 months) to win an ATP Challenger title and the second youngest to win multiple ATP Challenger titles. Auger-Aliassime won the 2016 US Open junior singles title and the 2015 US Open junior doubles title with compatriot Denis Shapovalov.
ground_truth: tennis