mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    NMAX = 4 * 10 ** 3
    is_prime = [1] * (NMAX + 1)
    is_prime[0] = is_prime[1] = 0
    for p in range(2, NMAX + 1):
        if not is_prime[p]:
            continue
        for d in range(2, NMAX + 1):
            if p * d > NMAX:
                break
            is_prime[p * d] = 0

    prime_list = []
    for p in range(2, NMAX + 1):
        if is_prime[p]:
            prime_list.append(p)

    ans = []
    M = int(input())
    i = 0
    for lv in range(30, 1, -1):
        k = 2 ** lv - 1
        if M >= k:
            M -= k
            p = prime_list[i]
            i += 1
            for _ in range(lv):
                ans.append(p * prime_list.pop())
    for _ in range(M):
        p = prime_list[i]
        i += 1
        ans.append(p * prime_list.pop())
        ans.append(p * prime_list.pop())

    print(len(ans))
    print(*ans)


if __name__ == '__main__':
    main()