from math import sqrt
N, K = map(int, input().split())

count = N // (K * K)
N -= count * K * K #残り塗らないといけない枚数
n = int(sqrt(N))
if n * n < N:
    n += 1

M = count * K + n
# print (count, N, n)
lst = [['.'] * M for _ in range(M)]
for i in range(count * K):
    for j in range(count * K):
        if i // K == j // K:
            lst[i][j] = '#'

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

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