first = raw_input()
split_first = first.split()
W = int(split_first[0])
H = int(split_first[1])
C = split_first[2]

if C == "B":
    A = "BW"*50

if C == "W":
    A = "WB"*50
    
for i in range(0,H):
    print A[i:i+W]