# あれ、グランディ数で解けない、なんでだろう?
# A = [0, 1, 3]でダメだ
# Bが圧倒的に有利、Bが負けるのはどんな初期状態かを考える
# 1が奇数個だけ、または1が奇数個で2が1つ、だけか

N = int(input())
A = list(map(int, input().split()))
count_1 = 0
count_2 = 0
count_3above = 0
for a in A:
    if a == 1:
        count_1 += 1
    elif a == 2:
        count_2 += 1
    elif a >= 3:
        count_3above += 1
nonzero = count_1 + count_2 + count_3above
ans = 'B'
if count_1 == nonzero:
    if count_1%2 == 1:
        ans = 'A'
else:
    if count_2 == 1 and count_1 + count_2 == nonzero and count_1%2 == 1:
        ans = 'A'
print(ans)
#print('count_1', count_1, 'count_2', count_2, 'count_3above', count_3above, 'nonzero', nonzero)