n = int(input())
do = [0]*(n+1)
for i in range(2,n+1):
    se = []
    se.append(do[i//2])
    if i%2 == 1:
        se.append(do[i//2+1])
    se.append(do[i//3])
    if i%3 != 0:
        se.append(do[i//3+1])
    ans = 0
    while ans in se:
        ans+=1
    do[i] = ans
print("B" if do[-1] == 0 else "A")