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

x,y = 0,0
for v in c:
    if v == 1:
        x += 1
    elif v > 1:
        y += 1

ans = 'B'
if y <= 1:
    num = x+2*y
    if num%2 == 1:
        ans = 'A'
print(ans)