def main():
    W, H, C = input().split()
    W = int(W)
    H = int(H)

    another_C = "W" if C == "B" else "B"

    for h in range(H):
        row = ""
        for w in range(W):
            match (w+h) % 2:
                case 0:
                    row += C
                case 1:
                    row += another_C
        print(row)


if __name__ == "__main__":
    main()