W,H,C = map(str,input().split())
W = int(W)
H = int(H)

flag = True if C =="B" else False
for y in range(H):
    s = ""
    for x in range(W):
        if flag:
            s += "B" if x%2 == 0 else "W"
        else:
            s += "W" if x%2 == 0 else "B"
    print(s)
    flag = not flag