#include <bits/stdc++.h>
using namespace std;
using llong = long long;

llong gcd(llong a, llong b)
{
    if (b == 0)
        return a;
    else
        return gcd(b, a % b);
}

int main() {
    llong n, d;
    cin >> n >> d;
    vector<llong> v(n);

    for (auto i = 0; i < n; i++)
    {
        cin >> v[i];
    }

    vector<llong> a;
    for (auto e : v)
        if (e % d == 0)
            a.push_back(e);

    vector<llong> res;
    for (auto e : a)
        if (gcd(d, e) == d)
            res.push_back(e);

    if (res.empty())
    {
        cout << -1;
        return 0;
    }

    cout << res.size() << endl;
    for (auto e : res)
        cout << e << " ";



    return 0;
}