w,h,c=input().split();f=[0,1][c=='W']
w,h=int(w),int(h)
for i in range(h):
	for j in range(w):
		if not w%2 and i%2:
			print(['B','W'][not f%2],end='')
		else:
			print(['B','W'][f%2],end='')
		f+=1
	print()