import functools


n = int(input())
c = sorted(map(int, input().split()))
a_is_winning = False
if (len(c) % 2 == 1 and c[-1] == 1) or \
   (len(c) >= 2 and len(c) % 2 == 0 and c[-1] == 2 and c[-2] == 1):
    a_is_winning = True
print('A' if a_is_winning else 'B')