import sys
W,H,C = raw_input().split()
W = int(W)
H = int(H)
D = ""
if (C == 'B'):
    D = 'W'
else:
    D = 'B'
for i in range(H):
    for j in range(W):
        if ((i + j) % 2 == 0):
            sys.stdout.write(C)
        else:
            sys.stdout.write(D)
    print