#include <bits/stdc++.h>

#define cin fin
#define cout fout
#define NMAX 1005
#define GMAX 50005

using namespace std;

ifstream cin("economie.in");
ofstream cout("economie.out");

int v[NMAX], sol[GMAX], n, cnt, ok[GMAX];

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> v[i];
    sort(v + 1, v + n + 1);
    for (int i = 1; i <= n; i++) {
        if (!ok[v[i]]) {
            ok[v[i]] = 1;
            sol[++cnt] = v[i];
        }
        for (int j = 1; j + v[i] <= 50000; j++) {
            if (ok[j]) {
                ok[j + v[i]] = 1;
            }
        }
    }
    cout << cnt << '\n';
    for (int i = 1; i <= cnt; i++)
        cout << sol[i] << ' ';
    return 0;
}