#include <fstream>
#include <algorithm>

using namespace std;

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

int v[1010],d[50010],sol[1010];
int n,i,j,k;

int main ()
{
    fin >> n;
    for (i=1; i<=n; i++)
        fin >> v[i];
    sort (v+1, v+n+1);
    d[0] = 1;
    for (i=1; i<=n; i++)
        if (d[v[i]] == 0)
        {
            sol[++k] = v[i];
            for (j=0; j+v[i]<=v[n]; j++)
                if (d[j] == 1)
                    d[j+v[i]] = 1;
        }
    fout << k << "\n";
    for (i=1; i<=k; i++)
        fout << sol[i] << "\n";
    return 0;
}