Context: Rafael Nadal Parera (Catalan: [rəf(ə)ˈɛl nəˈðal pəˈɾeɾə], Spanish: [rafaˈel naˈðal paˈɾeɾa];[6] born 3 June 1986) is a Spanish professional tennis player. He is currently ranked world No. 14 in singles by the Association of Tennis Professionals (ATP).[1] He has been ranked world No. 1 for 209 weeks, and has finished as the year-end No. 1 five times. He also holds the record for most consecutive weeks in the Top 10 of the ATP Rankings, having never left the Top 10 from April 2005 to March 2023, a total of 912 weeks. Nadal has won a joint-record 22 Grand Slam men's singles titles, including a record 14 French Open titles. He has won 92 ATP singles titles, including 36 Masters titles, with 63 of these on clay courts. Nadal is one of only two men to complete the Career Golden Slam in singles.[b] His 81 consecutive wins on clay is the longest single-surface win streak in the Open Era.

For over a decade, Nadal has dominated men's tennis along with Roger Federer and Novak Djokovic as the Big Three, collectively considered by many to be the three greatest male tennis players of all time.[c] At the start of his professional career, Nadal became one of the most successful teenagers in ATP Tour history, reaching the world No. 2 ranking and winning 16 titles before turning 20, including his first French Open and six Masters events. Nadal became the world No. 1 for the first time in 2008 after defeating Federer in a historic Wimbledon final, his first major victory off clay. He followed up his win with an Olympic singles gold at the 2008 Beijing Olympics. After defeating Djokovic in the 2010 US Open final, then-24-year-old Nadal became the youngest man in the Open Era to achieve the Career Grand Slam, and the first man to win majors on three different surfaces (hard, grass, and clay) in the same year (Surface Slam).

After two injury-plagued seasons, Nadal made a stellar return in one of the greatest comeback seasons of all time in 2013; reaching 14 finals, winning two majors and five Masters events including the US Open Series sweep (Summer Slam). He continued his dominance at the French Open, securing six titles, two US Open titles, an Australian Open title, and an Olympic doubles gold at the 2016 Rio Olympics with Marc López. Nadal surpassed his joint-record with Djokovic and Federer for the most major men's singles titles at the 2022 Australian Open, and became one of four men in history to complete the double Career Grand Slam in singles. He appeared in the Top 10 of the ATP rankings continuously from April 2005 to March 2023 – a record spanning 18 years.

As a vigorous left-handed player, one of Nadal's main strengths is his forehand, which he hits with extremely heavy topspin at difficult angles. He is one of the best at breaking serve, regularly appearing among the tour leaders in percentage of return games, return points, and break points won. Nadal has won the Stefan Edberg Sportsmanship Award five times, and was the Laureus World Sportsman of the Year in 2011 and 2021. He is also a recipient of the Grand Cross of the Order of Dos De Mayo, the Grand Cross of Naval Merit, and the Medal of the City of Paris. Representing Spain, he has won two Olympic gold medals, and led the nation to four Davis Cup titles. Nadal has also opened a tennis academy in Mallorca, and is an active philanthropist.
Question: Given the reference text about Rafael Nadal, tell me how many singles grand slam titles he has won, which grand slam tournament he has won the most, and the main strength of his tennis game.
Answer: Rafael Nadal has won 22 singles grand slam titles. The majority of his grand slam wins have been at the French Open, where he has won 14 times.

The main strength of his tennis game is his forehand because of his ability to hit the ball with extremely heavy topspin at difficult angles.