import string

W, H, C = raw_input().strip().split(" ")
w, h = int(W), int(H)
bw = ['B', 'W']
if C == 'W':
    bw = list(reversed(bw))
for i in range(0, h):
    row = []
    for j in range(0, w):
        row.append(bw[(i+j) & 1])
    print(string.join(row, ''))