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

box1 = box2 = 0

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

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