n=int(input())
def f(x):
	if x == 1:
		return ''
	if x % 2 == 1:
		y = g(x//2)
		if y is not None:
			return y + 'A'
	if x % 3 == 1:
		y = g(x//3)
		if y is not None:
			return y + 'B'
	return None


print(f(n))