W,H,C = input().split()
A = []
for i in range(int(H)):
    for x in range(int(W)):
        if C == "B":
            A.append("B")
            C = "W"
        else:
            A.append("W")
            C = "B"
    if int(W)%2 == 0:
        if C == "W":
            C = "B"
        else:
            C = "W"
    print("".join(A))
    A = []