def Piano(n,w):
	global binary

	if w == 0:
		for i in xrange(0,n):
			if binary[i] != 0:
				print("A")
				binary[i]=0
		print(binary)
	elif w == n:
		for i in xrange(0,n):
			if binary[i]!=1:
				print("B")
				binary[i]=1
		print(binary)
	elif w == 1:
		binary[n-1]=0
		Piano(n-1,w)
		binary[n-1]=1
		Piano(n-1,w-1)
	else:
		binary[n-1]=0
		Piano(n-1,w)

		binary[n-2]=0
		binary[n-1]=1
		Onaip(n-2,w-1)

		binary[n-2]=1
		Piano(n-2,w-2)

def Onaip(n,w):
	global binary
	if w == 0:
		for i in xrange(0,n):
			if binary[i]!=0:
				print("C")
				binary[i]=0
		print(binary)
	elif w == n:
		for i in xrange(0,n):
			if binary[i]!=1:
				print("D")
				binary[i]=1
		print(binary)
	elif w == 1:
		binary[n-1]=1
		Onaip(n-1,w-1)
		binary[n-1]=0
		Onaip(n-1,w)
	else:
		binary[n-2]=1
		binary[n-1]=1
		Onaip(n-2,w-2)

		binary[n-2]=0
		Piano(n-2,w-1)

		binary[n-1]=0
		Onaip(n-1,w)


binary=[0,0,0,0,0,0]
Piano(6,3)