n, k = map(int, input().split())
if n <= k**2:
    for i in range(1, k + 1):
        if i**2 >= n:
            ANS = [['#' for _ in range(i)] for _ in range(i)]
            if i**2 > n:
                cnt = i**2
                for j in range(i):
                    for jj in range(i):
                        ANS[j][jj] = '.'
                        cnt -= 1
                        if cnt == n:
                            break
                    if cnt == n:
                        break
            break
else:
    for i in range(k + 1, n + 1):
        if k * i >= n:
            ANS = [['.' for _ in range(i)] for _ in range(i)]
            for j in range(i):
                for jj in range(j, j + k):
                    ANS[j][jj % i] = '#'
            if k * i > n:
                cnt = k * i
                for j in range(i):
                    for jj in range(j, j + k):
                        ANS[j][jj] = '.'
                        cnt -= 1
                        if cnt == n:
                            break
                    if cnt == n:
                        break
            break
h = len(ANS)
print(h)
for i in range(h):
    print(''.join(ANS[i]))