import sys
input=lambda: sys.stdin.readline().rstrip()
w,h,c=map(str,input().split())
w=int(w)
h=int(h)
if c=="B":
  d="W"
else:
  d="B"
ans1=""
for i in range(w):
  if i%2==0:
    ans1+=c
  else:
    ans1+=d
ans2=""
for i in range(w):
  if i%2==1:
    ans2+=c
  else:
    ans2+=d
for i in range(h):
  if i%2==0:
    print(ans1)
  else:
    print(ans2)