You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you will be shown an extract from a movie plot and a question. You need to provide the correct answer for it. Short answers containing words that are present in the passage are preferred.

Twenty-year-old Will Hunting of South Boston is a self-taught, genius-level intellect, though he works as a janitor at the Massachusetts Institute of Technology and spends his free time drinking with his friends, Chuckie (Ben Affleck), Billy (Cole Hauser) and Morgan (Casey Affleck). When Professor Gerald Lambeau (Stellan Skarsgard) posts a difficult mathematics problem as a challenge for his graduate students, Will solves the problem anonymously, stunning both the graduate students and Lambeau himself. As a challenge to the unknown genius, Lambeau posts an even more difficult problem. Lambeau chances upon Will solving the problem but Will flees the scene. That night at a bar, Will meets Skylar (Minnie Driver), a British student about to graduate from Harvard, who plans on attending medical school at Stanford and gives Will her phone number before leaving., Question: How old is Will Hunting in the movie ?
Solution: Answer: Twenty years
Why? This is a good example which results in a factoid answer.

New input: In 1799, New York City police constable Ichabod Crane is dispatched by his superiors to the Hudson Highlands hamlet of Sleepy Hollow, to investigate a series of brutal slayings in which the victims have been found beheaded. A frequent user of new, though so far unproven investigative techniques such as finger-printing and autopsies, Crane arrives in Sleepy Hollow armed with his bag of scientific tools only to be informed by the town's elders that the murderer is not of flesh and blood, rather a headless supernatural warrior from beyond the grave who rides at night on a massive black steed.Crane does not believe them and begins his own investigation, until he comes face to "face" with the Headless Horseman. Boarding a room at the home of the town's richest family, the Van Tassels, Crane develops an attraction to their daughter, the mysterious Katrina, even as he is plagued by nightmares of his mother's horrific torture under his zealous preacher father when he was a child.Delving further into the mystery with the aid of the orphaned Young Masbeth, whose father was a victim of the Horseman, Crane discovers within the Western Woods both the Horseman's entry point between this world and the beyond, the gnarled Tree of the Dead with the heads of his victims within, and his grave. Ichabod discovers the horsemans skull is missing. The horsemen comes out of the tree and rides into town, taking two more victims. As the horseman leaves the house, It passes ichabod without killing him. Brom arrives and shoots at him; still the horseman doesnt try to kill him or brom. Brom finnaly pulls out a sword and duels with him, and the horseman finnaly kills brom. This prompts Crane to realise that someone must be using the skull to control the Horseman rather than the Horseman committing these murders of his own accord.Although evidence is briefly revealed suggesting that Katrina is the villain, Crane uncovers a murky plot revolving around revenge and land rights with the Horseman controlled by Katrina's stepmother, Lady Van Tassel, who sends the killer after her; her stepmother's family lost their land when her father died and it was given to Katrina's father, the young girl witnessing the Horseman's death and promising her soul to Satan if he would allow her to control the Horseman to avenge her family. Following a fight in the local windmill and a stagecoach chase through the woods, Crane eventually thwarts Lady Van Tassel by returning the skull to the Horseman, who regains his head and goes back to Hell along with Lady Van Tassel. With His job in Sleepy Hollow completed, Crane returns to New York with Katrina and Young Masbeth, just in time for the new century., Question: How is Lady Van Tassel able to control the Horseman?
Solution:
Answer: promised her soul to Satan