strinter = input()
strs = strinter.split(" ")

w_len= int(strs[0])
h_len= int(strs[1])
coler_s =strs[2]
data= ""
counter=1

for hei_t in range(h_len):
	for wei_t in range(h_len):
		if counter%2 ==1:
			data=data + coler_s
		else:
			if coler_s == "W":
				data=data + "B"
			else:
				data=data + "W"
		counter=counter+1
	print(data)
	data=""