W, H, C = input().split()
X = ['W', 'B']
X.remove(C)
C2 = X.pop()
W, H = int(W), int(H)
for i in range(H):
    cur = i%2
    ans = []
    for j in range(W):
        ans.append(cur)
        cur ^= 1
    ans = list(map(lambda x: C if x == 0 else C2, ans))
    print(''.join(ans))