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

for i in range(h):
    cur = 'B' if ((c == 'B') ^ (i % 2 == 1)) else 'W'
    for j in range(w):
        print(cur, end="")
        cur = 'B' if cur == 'W' else 'W'
    print()