#coding: utf-8
##yuki_82

s=[]
s=raw_input().split()
w=int(s[0])
h=int(s[1])
c=s[2]

ca=[]
for i in xrange(51):
 if i%2==0:
  ca.append('B')
 else:
  ca.append('W')

cb="".join(ca[:w])
cw="".join(ca[1:w+1])

if c=='B':
 for i in xrange(h):
  if i%2==0:
   print cb
  else:
   print cw
if c=='W':
 for i in xrange(h):
  if i%2==0:
   print cw
  else:
   print cb