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

    main_color = C
    if main_color == "B":
        sub_color = "W"
    else:
        sub_color = "B"

    for i in range(int(H)):
        for j in range(int(W)):
            if i == 0 or i % 2 == 0:
                if j == 0 or j % 2 == 0:
                    print(main_color, end='')
                else:
                    print(sub_color, end='')
            else:
                if j == 0 or j % 2 == 0:
                    print(sub_color, end='')
                else:
                    print(main_color, end='')
        print()


if __name__ == '__main__':
    main()