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

C2 = "W" if C =="B" else "B"
for y in range(H):
    s = ""
    for x in range(W):
        if (x+y)%2:
            s += C2
        else:
            s += C
    print(s)