import math
n, k = map(int, input().split(' '))

if n <= k**2:
    k = math.ceil(n**0.5)
    mod = n % k
    grid = ['#'*k for i in range(n//k)]
    if mod:
        grid.append(('#'*mod) + ('.'*(k-mod)))
    if len(grid) < k:
        grid.append('.'*k)

else:
    l = math.ceil(n/k)
    mod = n % k
    grid = [('#'*k) + ('.'*(l-k)) for i in range(n//k)]
    if mod:
        grid.append(('#'*mod) + ('.'*(l-mod)))

    for i in range(1, len(grid)):
        grid[i] = grid[i][i:] + grid[i][:i]

print(len(grid))
for row in grid:
    print(row)