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

q, r = divmod(N, K * K)
M = -K * (-N // (K * K))
G = [["." for _ in range(M)] for _ in range(M)]

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

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