N, K = map(int, input().split())

q, r = divmod(N, K * K)
M = K * q + r

print(M)

G = [["." for _ in range(M)] for _ in range(M)]
for i in range(0, M, K):
    j = i
    for di in range(K):
        for dj in range(K):
            if 0 <= i + di < M and 0 <= j + dj < M:
                G[i + di][j + dj] = "#"

for g in G:
    print("".join(g))