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

lst = [['.'] * M for _ in range(M)]

for i in range(M):
    for j in range(K):
        if N > 0:
            lst[i][(i + j) % M] = '#'
            N -= 1
        else:
            break

print (M)
for i in lst:
    print (*i, sep = '')