Problem:
Score : 100 points

Problem Statement

Snuke lives at position x on a number line.
On this line, there are two stores A and B, respectively at position a and b, that offer food for delivery.

Snuke decided to get food delivery from the closer of stores A and B.
Find out which store is closer to Snuke's residence.

Here, the distance between two points s and t on a number line is represented by |s-t|.

Constraints

1 \leq x \leq 1000

1 \leq a \leq 1000

1 \leq b \leq 1000

x, a and b are pairwise distinct.

The distances between Snuke's residence and stores A and B are different.

Input

Input is given from Standard Input in the following format:

x a b

Output

If store A is closer, print A; if store B is closer, print B.

Sample Input 1

5 2 7

Sample Output 1

B

The distances between Snuke's residence and stores A and B are 3 and 2, respectively.
Since store B is closer, print B.

Sample Input 2

1 999 1000

Sample Output 2

A

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

module Main (main) where

import qualified Data.ByteString.Char8     as C8
import           Data.Maybe

main :: IO ()
main = do
  [x,a,b] <- readInts
  print . showAnswer $ solve (x,a,b)

type Input  = (Int, Int, Int)
type Output = Bool

solve :: Input -> Output
solve (x,a,b) = (xa < xb)
  where
    xa = abs (x-a)
    xb = abs (x-b)

showAnswer :: Output -> Answer
showAnswer = AB

-- utils
readInts :: IO [Int]
readInts = map (fst . fromJust . C8.readInt) . C8.words <$> C8.getLine

data Answer
  = YesNo Bool
  | AB Bool

instance Show Answer where
  show (YesNo b) = if b then "Yes" else "No"
  show (AB b)    = if b then "A"   else "B"