import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

N, K = map(int,read().split())

def f(n, K):
    """n*n のグリッドに配置できる最大個数"""
    if K > n:
        K = n
    return n * K

def make_grid(n, K, N):
    if K > n:
        K = n
    x, y = np.meshgrid(np.arange(n), np.arange(n))
    I, J = np.where((x + y) % n < K)
    I = I[:N]
    J = J[:N]
    A = np.full((n,n), '.')
    A[I,J] = '#'
    return A

for n in range(1, N+10):
    if f(n, K) >= N:
        break
A = make_grid(n, K, N)

print(n)
print('\n'.join(''.join(row) for row in A))