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

if c == "B":
    d=0
else:
    d=1

for j in range(h):
    for i in range(w):
        if d %2 == 0:
            print("B", end="")
        else:
            print("W", end="")
        d += 1
    print("")