N, K = map(int, input().split())
sq = 0
for i in range(100):
    if (sq + 1) ** 2 < N:
        sq += 1

M = max(sq + 1, (N + K - 1)//K)
cnt = 0
print(M)
for i in range(M):
    ans = ["."] * M
    for j in range(min(M, K)):
        if cnt == N:
            continue
        ans[(i + j)%M] = "#"
        cnt += 1
    print(*ans, sep="")