# Grundy数でダメだった、確かに[1, 3]はGrundy数だと勝てるはずだけど負ける
# 先攻が勝てるのは手番で[1]または手番が終わって[1, 1]
# そうなるのは1が奇数個と2が1個だけか

N = int(input())
C = list(map(int, input().split()))
one_count = 0
two_or_more_count = 0
for i in range(N):
    if C[i] == 1:
        one_count += 1
    elif C[i] > 1:
        two_or_more_count += 1
if one_count%2 == 1 and two_or_more_count == 0:
    print('A')
elif one_count%2 == 1 and two_or_more_count == 1:
    print('A')
else:
    print('B')