n = int(input())
C = list(map(int, input().split()))

box1 = box2 = box3 = 0

for c in C:
    if c == 1:
        box1 += 1
    elif c == 2:
        box2 += 1
    elif c > 2:
        box3 += 1

if box1 % 2 == 1 and box2 <= 1 and box3 == 0:
    print("A")
else:
    print("B")