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

q, r = divmod(N, K * K)
R = int(r ** 0.5)
if R * R < r:
    R += 1
M = K * q + R
G = [["." for _ in range(M)] for _ in range(M)]

for i in range(0, M - R, 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] = "#"
count = 0
for i in range(R):
    for j in range(R):
        if count >= r:
            break
        G[K * q + i][K * q + j] = "#"
        count += 1

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