N, K = map(int, input().split())
M = (N + (K - 1)) // K

if M < K:
    from math import sqrt
    n = int(sqrt(N))
    if n * n < N:
        n += 1
    M = n
    lst = [['.'] * M for _ in range(M)]
    for i in range(M):
        for j in range(M):
            if N > 0:
                lst[i][j] = '#'
                N -= 1
    print (M)
    for i in lst:
        print (*i, sep = '')
    exit()


lst = [['.'] * M for _ in range(M)]

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

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