#include <bits/stdc++.h>
#define ll long long
#define LMAX 50000
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
int n, el, v[1005];
vector <int> rez;
bool ok[LMAX + 5];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    fin >> n;
    for (int i = 1; i <= n; ++i)
        fin >> v[i];
    sort(v + 1, v + n + 1);
    for (int i = 1; i <= n; ++i) {
        if (!ok[v[i]]) {
            rez.push_back(v[i]);
            ok[v[i]] = true;
            for (int j = 1; j + v[i] <= LMAX; ++j)
                if (ok[j])
                    ok[j + v[i]] = true;
        }
    }
    fout << rez.size() << "\n";
    for (int i = 0; i < rez.size(); ++i)
        fout << rez[i] << "\n";
    return 0;
}