#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin ("economie.in");
ofstream fout ("economie.out");
int n,i,k,j,v[1001],h[1001],f[50001];
int main()
{
    fin>>n;
    for (i=1; i<=n; i++)
        fin>>v[i];
    sort (v+1,v+n+1);
    f[0]=1;
    for (i=1; i<=n; i++)
    {
        if (f[v[i]]==0)
        {
            k++;
            h[k]=v[i];
        }
        for (j=0; j+v[i]<=v[n]; j++)
        {
            if (f[j]==1)
                f[j+v[i]]=1;
        }
    }
    fout<<k<<"\n";
    for (i=1; i<=k; i++)
        fout<<h[i]<<" ";
    return 0;
}