N, K = map(int, input().split())
k = (N-1+K) // K
if k < K:
    k = 0
    while k**2 < N:
        k += 1
    R = [['.']*(k) for i in range(k)]
    for i in range(k):
        for j in range(k):
            if N > 0:
                R[i][j] = '#'
                N -= 1
else:
    R = [['.']*(k) for i in range(k)]
    for i in range(k):
        for j in range(K*i, K*i+K):
            if N > 0:
                R[i][j % k] = '#'
                N -= 1
print(k)
for line in R:
    print(*line, sep='')