import math
import sys

from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines

W,H,C=readline().split()
H=int(H)
W=int(W)
if C=='B':
    CC='W'
else:
    CC='B'
ans_lst=[[C if h%2==w%2 else CC for w in range(W)] for h in range(H)]
for ans in ans_lst:
    print(*ans,sep='')