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

l = 'BW' * 26
l1 = [l[1:w+1], l[0:w]][s == 'B']
l2 = [l[0:w], l[1:w+1]][s == 'B']

for i in range(h):
    if i % 2 == 0:
        print(l1)
    else:
        print(l2)