Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Input: Consider Input: Context: To evaluate short- and mid-term level of imbalance after vestibular schwannoma (VS) microsurgery by the transpetrosal approach, to search for factors predictive of vestibular compensation, and to determine which patient categories need a postoperative vestibular rehabilitation program. Prospective cohort study at a tertiary referral center. Between 2010 and 2011, patients aged 18 to 75 operated on for VS by transpetrosal approaches were included. VS was characterized by its size (Koos classification) and the presence or not of a cystic component. Hearing was classified according to the Gardner Robertson grading. The preoperative workup included an audiogram, computerized video nystagmography (VNG) with caloric testing, gaze study, rotatory tests, click-evoked cervical vestibular evoked myogenic potential measurements (cVEMPs), and subjective visual vertical test. Patients were asked to complete a Dizziness Handicap Inventory (DHI). Postoperatively, patients were reevaluated on D7 (clinical status), D90 (VNG and DHI), and D180 (DHI). Timing and duration of vestibular rehabilitation were also recorded. Forty-eight patients were included. Preoperatively, 77% experienced mild instability problems with a mean DHI score of 14.1 (range 4-32). Postoperatively, 71% reported stable or even improved perceived stability. Mean DHI scores were 28.1 on D90 and 19.8 on D180. Serviceable hearing, cystic transformation, normal cVEMPs, diplopia, and vestibular syndrome on D7 were found to be predictive of worse equilibrium outcome than when absent. A preoperative caloric deficit greater than 75% seemed to be a good prognostic factor. Vestibular rehabilitation was conducted in 56% of patients. Starting it early (<1 mo) seemed to be beneficial for final equilibrium outcome. VS microsurgery provides good stability results. Some preoperative parameters may be predictive of worse or improved balance recovery, as is clinical status on D7. 
 Question: Which disease can be categorized using the Koos grading system?

Output: vestibular schwannoma


Input: Consider Input: Context: Long long ago, there was an old merchant who had three sons. "To which one shall I leave my fortune?" he wondered. "It must be to the cleverest son. But which one is the cleverest?" He called his three sons to him. "Here is some money," he told them, "you must each take one coin to buy something that will fill this room. Anyone who can do this shall have my fortune." "It is a big room," said the eldest son. "One coin will not buy very much," said the second son. But the youngest son said nothing. He stood and thought, and then he smiled, "Come, brothers," he said, "let us go to the market." The eldest son bought straw with his coin. But one coin bought only a bit of straw. Even when he had spread it as much as he could, the straw covered only a corner of the room. The second son bought sand with his coin. But one coin bought only a bit of sand. Even when he had spread it as much as he could, the sand covered only half of the floor. "What did you buy?" the eldest son angrily asked the youngest son. "You don't have any straw." "Yes, what did you buy?" the second son asked angrily. "You don't have any sand." "I bought this," said the youngest son. "A candle!" cried his brothers. "What good is a candle?" "Watch", said the youngest son. He lit the candle, and all at once the room was filled from wall to wall, from ceiling to floor. It was filled with light! "Although you are the youngest, you are indeed the cleverest of my sons," the old merchant said. And that is how, the old merchant left his fortune to his youngest son, the one who could fill a room with light. 
 Question: Who would get father's fortune?

Output: the cleverest son.


Input: Consider Input: Context: Histone H3 lysine 9 (H3K9) methylation is a major component of gene regulation and chromatin organization. SUV39H1 methylates H3K9 at the pericentric heterochromatin region and participates in the maintenance of genome stability. In this study, a recombinant purified SUV39H1 is used for substrate specificity and steady-state kinetic analysis with peptides representing the un- or dimethylated lysine 9 histone H3 tail or full-length human recombinant H3 (rH3). Recombinant SUV39H1 methylated its substrate via a nonprocessive mechanism. Binding of either peptide or AdoMet first to the enzyme made a catalytically competent binary complex. Product inhibition studies with SUV39H1 showed that S-adenosyl-l-homocysteine is a competitive inhibitor of S-adenosyl-l-methionine and a mixed inhibitor of substrate peptide. Similarly, the methylated peptide was a competitive inhibitor of the unmethylated peptide and a mixed inhibitor of AdoMet, suggesting a random mechanism in a bi-bi reaction for recombinant SUV39H1 in which either substrate can bind to the enzyme first and either product can release first. The turnover numbers (k(cat)) for the H3 tail peptide and rH3 were comparable (12 and 8 h(-)(1), respectively) compared to the value of 1.5 h(-)(1) for an identical dimethylated lysine 9 H3 tail peptide. The Michaelis constant for the methylated peptide (K(m)(pep)) was 13-fold lower compared to that of the unmethylated peptide. The Michaelis constants for AdoMet (K(m)(AdoMet)) were 12 and 6 microM for the unmethylated peptide substrate and rH3, respectively. A reduction in the level of methylation was observed at high concentrations of rH3, implying substrate inhibition. Deletion of the chromodomain or point mutation of the conserved amino acids, W64A or W67A, of SUV39H1 impaired enzyme activity despite the presence of an intact catalytic SET domain. Thus, SUV39H1 utilizes both the chromodomain and the SET domain for catalysis. 
 Question: What is the characteristic domain of histone methyltransferases?


Output: set domain