wt,ht,c = input().split()
w,h = int(wt),int(ht)
if c == "W":
	mode = 0
else:
	mode = 1
for i in range(h):
	ansl = []
	if (i+mode) % 2 == 0:
		for j in range(w):
			if j % 2 == 0:
				ansl.append("W")
			else:
				ansl.append("B")
	else:
		for j in range(1,w+1):
			if j % 2 == 0:
				ansl.append("W")
			else:
				ansl.append("B")
	print("".join(ansl))