rr = raw_input
rri = lambda: int(raw_input())
rrm = lambda: map(int, raw_input().split())

def make(N, K, tot):
    otot = tot
    ans = [['.'] * N for _ in xrange(N)]
    for r, row in enumerate(ans):
        for c, v in enumerate(row):
            zr = r / K
            zc = c / K
            if zr == zc and tot:
                ans[r][c] = '#'
                tot -= 1
    if tot: return make(N+1, K, otot)
    return ans
def solve(tot, K):
    # tot - total #'s
    # K - max #'s per row/col
    q,r = divmod(tot, K)
    N = q + (r > 0)

    return make(N, K, tot)

ans = solve(*rrm())
print len(ans)
for row in ans:
    print "".join(row)