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

if w == h == 1:
    print(s)

else:
    if s == 'B':
        t = 'W'
    else:
        t = 'B'
    
    x = (s + t) * int((w+1)/2)
    x = x[:w]
    y = (t + s) * int((w+1)/2)
    y = y[:w]
    
    z = (x + y) * int((h+1)/2)

    z = [z[i:i+w] for i in range(0, len(z), w)] 
    
    for i in range(h):
        print(z[i])