W, H, C = input().split()

BW = "BW" * 100
WB = "WB" * 100

if C == 'B':
    for i in range(int(H)):
        if i % 2 == 0:
            print(BW[:int(W)])
        else:
            print(WB[:int(W)])

elif C == "W":
    for i in range(int(H)):
        if i % 2 == 0:
            print(WB[:int(W)])
        else:
            print(BW[:int(W)])