import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N = I()
Grundy = [-1]*(N+1)
Grundy[1] = 0

for i in range(2,N+1):
    X = set()
    if i % 2 == 0:
        X.add(0)
    else:
        X.add(Grundy[i//2] ^ Grundy[i//2+1])
    if i % 3 == 0:
        X.add(Grundy[i//3])
    elif i % 3 == 1:
        X.add(Grundy[i//3+1])
    else:
        X.add(Grundy[i//3])
    for j in range(100):
        if not j in X:
            Grundy[i] = j
            break

print('A' if Grundy[-1] != 0 else 'B')