#include <fstream>
#include <algorithm>
using namespace std;

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

const int MAXN = 1000;
const int MAXVAL = 50000;

int v[1 + MAXN], answer[1 + MAXN];
bool seen[1 + MAXVAL];

int main() {
    int n, coins = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> v[i];
    sort(v + 1, v + n + 1);
    seen[0] = true;
    for (int i = 1; i <= n; i++)
        if (!seen[v[i]]) {
            coins++;
            answer[coins] = v[i];
            for (int j = 0; j + v[i] <= v[n]; j++)
                if (seen[j])
                    seen[j + v[i]] = true;
        }
    cout << coins << "\n";
    for (int i = 1; i <= coins; i++)
        cout << answer[i] << "\n";
    return 0;
}