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

def make(N, K, 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
    return ans

def solve(tot, K):
    def carry(n):
        ans = 0
        while n > 0:
            delta = min(n, K)
            ans += delta * delta
            n -= delta
        return ans

    n = 1
    while carry(n) < tot:
        n += 1
    return make(n, K, tot)

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