import bisect import copy import decimal import fractions import heapq import itertools import math import random import sys import time from collections import Counter,deque,defaultdict from functools import lru_cache,reduce from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max def _heappush_max(heap,item): heap.append(item) heapq._siftdown_max(heap, 0, len(heap)-1) def _heappushpop_max(heap, item): if heap and item < heap[0]: item, heap[0] = heap[0], item heapq._siftup_max(heap, 0) return item from math import gcd as GCD read=sys.stdin.read readline=sys.stdin.readline readlines=sys.stdin.readlines write=sys.stdout.write #import pypyjit #pypyjit.set_param('max_unroll_recursion=-1') #sys.set_int_max_str_digits(10**9) N=int(readline()) C=list(map(int,readline().split())) C1,C2=C.count(1),C.count(2) if C1==N and N%2: ans="A" elif C2==1 and C1==N-1 and N%2==0: ans="A" else: ans="B" print(ans)