seq = input().split()

x = int(seq[0])
y = int(seq[1])
c = seq[2]

BW = []
for i in range(30):
    BW.append("BW")
BWseq = "".join(BW)

WB = []
for i in range(30):
    WB.append("WB")
WBseq = "".join(WB)

if c == "W":
    for i in range(y):
        if i % 2 == 1:
            print(BWseq[0:x])
        else:
            print(WBseq[0:x])
else:
    for i in range(y):
        if i % 2 == 1:
            print(WBseq[0:x])
        else:
            print(BWseq[0:x])