w,h,c=input().split()

if c=="B":
    d="BW"
    e="W"
    f="WB"
else:
    d="WB"
    e="B"
    f="BW"
w=int(w)
h=int(h)
a=w%2
b=w//2
if a==1:
    s=d*b+c
    t=f*b+e
else:
    s=d*b
    t=f*b
for i in range(h):
    if i%2==0:
        print(s)
    else:
        print(t)