Question: What is the name of the first novel in the series that the television series starring Benedict Cumberbatch is based on?

Context paragraphs:
The Empty Hearse: "The Empty Hearse" is the first episode of the third series of the BBC television series "Sherlock".  It was written by Mark Gatiss and stars Benedict Cumberbatch as Sherlock Holmes, Martin Freeman as Dr John Watson, and Mark Gatiss as Mycroft Holmes.  It also marks the first appearance of Amanda Abbington as Mary Morstan and Lars Mikkelsen as Charles Augustus Magnussen.

Tinker Tailor Soldier Spy (film): Tinker Tailor Soldier Spy is a 2011 Cold War espionage film directed by Tomas Alfredson.  The screenplay was written by Bridget O'Connor and Peter Straughan, based on John le Carré's 1974 novel of the same name.  The film, starring Gary Oldman as George Smiley, along with Colin Firth, Tom Hardy, John Hurt, Toby Jones, Mark Strong, Benedict Cumberbatch, and Ciarán Hinds, and featuring David Dencik, is set in London in the early 1970s and follows the hunt for a Soviet double agent at the top of the British secret service.

Doctor Strange (2016 film): Doctor Strange is a 2016 American superhero film based on the Marvel Comics character of the same name, produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures.  It is the fourteenth film of the Marvel Cinematic Universe (MCU).  The film was directed by Scott Derrickson, who wrote it with Jon Spaihts and C. Robert Cargill, and stars Benedict Cumberbatch as Stephen Strange, along with Chiwetel Ejiofor, Rachel McAdams, Benedict Wong, Michael Stuhlbarg, Benjamin Bratt, Scott Adkins, Mads Mikkelsen, and Tilda Swinton.  In "Doctor Strange", surgeon Strange learns the mystic arts after a career-ending car accident.

The Sign of Three: "The Sign of Three" is the second episode of the third series of the BBC television series "Sherlock".  It was written by Stephen Thompson, Mark Gatiss and Steven Moffat and stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Dr John Watson.  The episode's title is inspired by "The Sign of the Four" by Sir Arthur Conan Doyle.  It is set six months after the series opener "The Empty Hearse" and is primarily centred on the day of Watson's wedding to Mary Morstan.  It garnered a viewership of 11.37 million, and received mostly positive reviews.

The Last Enemy (TV series): The Last Enemy is a 5-part BBC television drama starring Benedict Cumberbatch and featuring Robert Carlyle and Max Beesley.  It first aired on 17 February 2008.

Sherlock (TV series): Sherlock is a crime drama television series based on Sir Arthur Conan Doyle's Sherlock Holmes detective stories.  Created by Steven Moffat and Mark Gatiss, it stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Doctor John Watson.  Thirteen episodes have been produced, with three-part series airing from 2010–2017, and a special episode that aired on 1 January 2016.  The series is set in the present day, while the one-off special features a Victorian period fantasy resembling the original Holmes stories.  "Sherlock" is a co-production of the British network BBC and the American station WGBH Boston for its "Masterpiece" anthology series on PBS, along with Hartswood Films, with Moffat, Gatiss, Sue Vertue and Rebecca Eaton serving as executive producers.  The series is primarily filmed in Cardiff, Wales, with North Gower Street in London used for exterior shots of Holmes and Watson's 221B Baker Street residence.

Adelaide Clemens: Adelaide Clemens (born 30 November 1989) is an Australian actress.  She was nominated for a Logie Award in 2008 for her role in the television series "Love My Way".  In 2012, she played Valentine Wannop in BBC's novel adaptation "Parade's End", alongside Benedict Cumberbatch.  Clemens has also appeared in "", "The Great Gatsby", and "" (as Heather Mason).  From 2023-2016, she starred in the television series "Rectify".

Arthur Conan Doyle: Sir Arthur Ignatius Conan Doyle KStJ, DL (22 May 1859 – 7 July 1930) was a British writer best known for his detective fiction featuring the character Sherlock Holmes.  Originally a physician, in 1887 he published "A Study in Scarlet", the first of four novels about Holmes and Dr. Watson.  In addition, Doyle wrote over fifty short stories featuring the famous detective.

Hattie Dalton: Hattie Dalton is an Australian filmmaker who won a BAFTA award for best live-action short film for her 2004 film "The Banker", starring Michael Sheen.  She also directed 2010 feature film "Third Star" starring Benedict Cumberbatch.

Third Star: Third Star is a 2010 British drama film directed by Hattie Dalton and starring Benedict Cumberbatch, JJ Feild, Tom Burke, Adam Robertson, and Hugh Bonneville.  It premiered at the Edinburgh Film Festival in June 2010, where it was shown as the closing film, and was released in the United Kingdom on 20 May 2011.

Supporting paragraphs: Sherlock (TV series) Arthur Conan Doyle
Answer: "A Study in Scarlet"