n=int(input())
g=[0]*(n+1)

def  ni(x):
    if x%2:return x//2,x//2 + 1
    else:return x//2,x//2

def  san(x):
    t=x//3
    if x%3 == 0:
        return t,t,t
    elif t*3 + 1 == x:
        return t,t,t+1
    elif t*3 + 2 == x:
        return t,t+1,t+1

    return False
    

for i in range(2,n+1):
    s = set()
    nit = ni(i)
    t = 0
    for j in nit:
        t^=g[j]
    s.add(t)
    t=0
    sat = san(i)
    for j in sat:
        t^=g[j]
    s.add(t)
    p = 0
    while p in s:
        p +=  1
    # print(p,i)
    g[i] = p

print('A' if g[n] > 0 else 'B')