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)


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

    # MEX (定義通り)
    for j in range(100):
        if j not in st:
            dp[i] = j
            break

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