import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N,*C = map(int,read().split())

S = sum(C)
T = sum(x-1 if x >= 2 else 0 for x in C)

answer = 'A' if S&1 and T <= 1 else 'B'
print(answer)