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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<int> a(n), ans;
    for(auto &&v : a) cin >> v;
    sort(a.begin(), a.end());
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    ans.emplace_back(a[1]);
    pq.emplace(2 * a[1], a[1]);
    for(int i = 2; i < n; i++){
        if(pq.top().first < a[i]){
            cout << -1 << '\n';
            return 0;
        }
        bool flg = true;
        while(a[i] == pq.top().first){
            auto [v, d] = pq.top();
            pq.emplace(v + d, d);
            pq.pop();
            flg = false;
        }
        if(flg){
            ans.emplace_back(a[i]);
            pq.emplace(2 * a[i], a[i]);
        }
    }

    if(pq.top().first <= m){
        cout << -1 << '\n';
        return 0;
    }

    cout << ans.size() << '\n';
    for(int i = 0; i < ans.size(); i++){
        cout << ans[i] << (i + 1 == ans.size() ? '\n' : ' ');
    }
}