N = int(input())

dp = [0] * (N + 1)


def div2(n):
    n2 = n // 2
    if n % 2 == 1:
        return (n2, n2 + 1)
    else:
        return (n2, n2)


def div3(n):
    n3 = n // 3
    if n % 3 == 1:
        return (n3, n3, n3 + 1)
    elif n % 3 == 2:
        return (n3, n3 + 1, n3 + 1)
    else:
        return (n3, n3, n3)


# 1: 負け (G1=0)
# 2: 1, 1で (G2 =1+0^0)
# 3: 1, 2 か 1, 1, 1 (G3 = 1+0^1 ^ 1+0^0^0)

for i in range(2, N + 1):
    d2 = div2(i)
    grundy_2 = 1 + (dp[d2[0]] ^ dp[d2[1]])
    if i == 2:
        dp[i] = grundy_2
        continue
    d3 = div3(i)
    grundy_3 = 1 + (dp[d3[0]] ^ dp[d3[1]] ^ dp[d3[2]])
    dp[i] = grundy_2 ^ grundy_3

print("B" if dp[N] == 0 else "A")