def f(c):
    if c == 'B':
        return 'W'
    else:
        return 'B'

w, h, c = input().split()
w = int(w)
h = int(h)
for i in range(h):
    for j in range(w):
        if (i + j) % 2 == 0:
            print(c, end="")
        else:
            print(f(c), end="")
    print("")