w,h,c = raw_input().split()
w = int(w)
h = int(h)
l = [['' for _ in range(w)] for _ in range(h)]
s = ['B','W']
d = 0 if c == 'B' else 1
for y in range(h):
    for x in range(w):
        l[y][x] = s[(x+y+d) % 2]
for t in l:
    print ''.join(t)