w,h,c = input().split()
w = int(w)
h = int(h)

for j in range(h):
    for i in range(w):
        if c =="B":
            if (i+j)%2 == 0:
                print("B", end="")
            else:
                print("W", end="")
        else:
            if (i+j)%2 == 0:
                print("W", end="")
            else:
                print("B", end="")
    print("")