# your code goes here
W,H,C=input(). split ()
W=int(W)
H=int(H)
Bo=["B"]*H
#rint (Bo)
if C=="B":
    D="W"
else:
    D="B"
i=0
while i<H:
    j=0
    while j <W:
        N=i+j
        if N%2==1:
            Bo[i]+=D
        else:
            Bo[i]+=C
        j+=1
   #     print (i)
     #   print (Bo[1])
    i+=1
for i in range (H):
    Ou=list (Bo[i])
    Ou.pop(0)
    print("".join(Ou))