#include<fstream>
#include<algorithm>
using namespace std;
ifstream in ("economie.in");
ofstream out ("economie.out");
int n,sol,val[1001],d[50001],x,rez[1001];
int main (void) {
    in >> n;
    for (int i = 1; i <= n; i ++) {
        in >> val[i];
    }
    sort (val+1,val+n+1);
    d[0] = 1;
    for (int i = 1; i <= n; i ++) {
        if (d[val[i]] == 0) {
            for (int j = val[i]; j <= 50000; j ++) {
                if (d[j-val[i]] == 1) {
                    d[j] = 1;
                }
            }
            rez[++sol] = val[i];
        }
    }
    out << sol <<"\n";
    for (int i = 1; i <= sol; i ++) {
        out << rez[i] <<"\n";
    }
}