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

int main() {
    ifstream fin("economie.in");
    ofstream fout("economie.out");

    int N;
    fin >> N;

    vector<int> coins(N);
    for (int i = 0; i < N; i++)
        fin >> coins[i];

    sort(coins.begin(), coins.end());

    vector<int> subset;
    long long S = 0;
    for (int x : coins) {
        if (x <= S + 1) {
            subset.push_back(x);
            S += x;
        }
    }

    fout << subset.size() << "\n";
    for (int x : subset)
        fout << x << "\n";

    return 0;
}