def main():
    _ = int(input())
    C = list(map(int, input().split()))

    if sum(C) % 2 == 0:
        print("B")
        return
    
    B_choice = list(filter(lambda num: num >= 2, C))
    if not B_choice:
        print("A")
        return
    if len(B_choice) >= 2:
        print("B")
        return
    if B_choice[0] > 2:
        print("B")
    else:
        print("A")




if __name__ == "__main__":
    main()