#include <fstream>
#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];
        if(d[v[i]] == false)
        {
            d[v[i]] = true;
            ans.push_back(v[i]);
            for(int j=0; j<=nmax; j++)
            {
                d[j+v[i]] = true;
            }
        }
    }
    out<<ans.size()<<"\n";
    for(int i=0; i<ans.size(); i++)
    {
        out<<ans[i]<<"\n";
    }
    return 0;
}