n = int(input())
*a, = map(int,input().split())
v = [0,0,0,0]
for ai in a:
    v[min(ai,3)] += 1
win = 0
if v[3] >= 1: win = 1
if v[2] >= 2: win = 1
if (2*v[2] + v[1])%2 == 0: win = 1
print("AB"[win])