# 2016.2.13
inp = raw_input().split()
W = int(inp[0])
H = int(inp[1])
C = inp[2]
simaA = []
simaB = []
tag = C
for i in range(0,W):
    if tag == "W":
        simaA.append(tag)
        tag = "B"
        simaB.append(tag)
    else:
        simaA.append(tag)
        tag = "W"
        simaB.append(tag)
flag = "simaA"
for i in range(0, H):
    if flag == "simaA":
        print "".join(simaA)
        flag = "simaB"
    else:
        print "".join(simaB)
        flag = "simaA"