#include <fstream>
#include <algorithm>
#include <vector>
#define nmax 50005

using namespace std;

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

int n;

vector<int> ans;

int  v[nmax];

bool d[nmax];

int main()
{
    in>>n;
    d[0] = 1;
    for(int i=1; i<=n; i++)
    {
        in>>v[i];
    }
    sort(v+1, v+n+1);
    for(int i=1; i<=n; i++)
    {
        if (d[v[i]] == false) {
            d[v[i]] = true;
            ans.push_back(v[i]);
            for (int j = 0; j < nmax - v[i]; j++) {
                if (d[j] == true) {
                    d[j + v[i]] = true;
                }
            }
        }
    }
    out<<ans.size()<<"\n";
    for(int i=0; i<ans.size(); i++)
    {
        out<<ans[i]<<"\n";
    }
    return 0;
}