type Point    = Float
type Distance = Float

distance :: (Point,Point) -> Distance
distance = abs . uncurry (-)

main :: IO ()
main = do
  [x,a,b] <- map read . words <$> getLine

  let da = distance (a,x)
      db = distance (b,x)

  case compare da db of
    LT -> putChar 'A'
    GT -> putChar 'B'
