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

l = 'BW' * 26
if s == 'B':
    l1 = l[0:w]
    l2 = l[1:w+1]
else:
    l1 = l[1:w+1]
    l2 = l[0:w]
    
for i in range(h):
    if i % 2 == 0:
        print(l1)
    else:
        print(l2)