{-# LANGUAGE BangPatterns #-}
import Control.Applicative((<$>))
import Control.Monad
import qualified Data.Map as M
-- import qualified Data.Char as C
import qualified Data.List as L
-- import qualified Data.IntSet as I
-- import Debug.Trace
--------------------------------------------
readInt    = read :: String -> Int
readFloat  = read :: String -> Float
getInt     = readInt <$> getLine
getIntList = map readInt . words <$> getLine
int2bin 0 =  []
int2bin n =  n `mod` 2 : int2bin (n `div` 2)
----------------------------------------------

main :: IO ()
main = do
  [x,a,b] <- getIntList
  putStrLn $ if abs(x-a) <= abs(x-b) then "A" else "B"
