# 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が奇数個だけ
# 1が奇数個と2が1個だけか
# 3以上が入ればダメ

N = int(input())
C = list(map(int, input().split()))
one_count = 0
two_count = 0
three_above = 0
for i in range(N):
    if C[i] == 1:
        one_count += 1
    elif C[i] == 2:
        two_count += 1
    elif C[i] >= 3:
        three_above += 1    
if one_count%2 == 1 and two_count == 0 and three_above == 0:
    print('A')
elif one_count%2 == 1 and two_count == 1 and three_above == 0:
    print('A')
else:
    print('B')