#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");

const int MAXN = 1005;
const int MAXV = 50005;
int n;
int v[MAXN];
bool c[MAXV];
int t, sol[MAXN];
int maxx;

int main() {
    fin >> n;
    for (int i = 1; i <= n; ++i) {
        fin >> v[i];
        maxx = max(maxx, v[i]);
    }
    sort(v + 1, v + n + 1);
    for (int i = 1; i <= n; ++i) {
        if (c[v[i]] == 0) {
            sol[++t] = v[i];
            c[v[i]] = 1;
            int l = MAXV - v[i];
            for (int j = 1; j < l; ++j) {
                if (c[j] == 1) {
                    c[j + v[i]] = 1;
                }
            }
        }
    }
    fout << t << '\n';
    for (int i = 1; i <= t; ++i) {
        fout << sol[i] << '\n';
    }
    fout.close();
    return 0;
}