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

s = 25 * ('BW', 'WB')[c != 'B']
t = 25 * ('WB', 'BW')[c != 'B']

if h % 2 == 0:
    for i in range(h//2):
        print(s[:w])
        print(t[:w])
else:
    for i in range(h//2):
        print(s[:w])
        print(t[:w])
    print(s[:w])