N, K = map(int, input().split())
k = (N-1+K) // K
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='')