w,h,c = input().split()
w  = int(w)
h = int(h)
str1 = "".join(["W" if i%2==0 else "B" for i in range(w)])
str2 = "".join(["B" if i%2==0 else "W" for i in range(w)])
for i in range(h):
   if c=="W":
        if i%2==0:
            print(str1)
        else:
            print(str2)
   else:
       if i%2==0:
            print(str2)
       else:
            print(str1)