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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,M; cin >> N >> M;
    vector<int> A(N);
    for(auto &a : A) cin >> a;
    sort(A.begin(),A.end());

    priority_queue<pair<int,int>,vector<pair<int,int>>,greater<>> Q;
    bool ok = true;
    vector<int> B;
    for(int i=1; i<N; i++){
        int a = A.at(i);
        bool already = false;
        while(Q.size()){
            auto [t,add] = Q.top();
            if(t > a) break;
            else if(t < a){ok = false; break;}
            Q.pop(); Q.push({t+add,add});
            already = true;
        }
        if(!ok) break;
        if(!already) Q.push({a+a,a}),B.push_back(a);
    }
    if(Q.top().first <= M || !ok) cout << "-1" << endl;
    else if(ok){
        cout << B.size() << endl;
        for(auto &b : B) cout << b << " "; cout << endl;
    }
    else cout << -1 << endl;
}