W, H, C = input().split()
W, H = int(W), int(H)
if C == "B":
	D = "W"
else:
	D = "B"
	
for i in range(H):
	ans = []
	for j in range(W):
		if (i + j) % 2:
			ans.append(D)
		else:
			ans.append(C)
	print(*ans, sep="")