M = ['B', 'W']
W, H, C = map(str, input().split())
W, H = int(W), int(H)
for i in range(H):
	for j in range(W):
		if(C == 'B'):
			print(M[(i + j)%2], end='')
		else:
			print(M[(i + j)%2 - 1], end='')
	print()