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

if N <= K:
    M = int(sqrt(N))
    if M * M < N:
        M += 1
    print (M)
    for i in range(M):
        for j in range(M):
            if N > 0:
                print ('#', end = '')
                N -= 1
            else:
                print ('.', end= '')
        print()
    exit()


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

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