import sequtils,algorithm,math
proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    let k = getchar_unlocked()
    if k < '0': break
    result = 10 * result + k.ord - '0'.ord

let n = scan()
let C = newSeqWith(n,scan()).sorted(cmp).filterIt(it>0)
if C.len == 0 : echo "B"
elif C.len == 1:
  if C[0] == 1: echo "A"
  else: echo "B"
elif C[^1] >= 2:
  if C == @[1,2] : echo "A"
  else: echo "B"
else:
  if C.sum() mod 2 == 1 : echo "A"
  else: echo "B"