# include <fstream>
# include <algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
int d[50010],v[1010],sol[1010],n,k,i,j;
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[n];j++)
                if(j+v[i]<=v[n]&&d[j]==1)
                    d[j+v[i]]=1;
        }
    fout<<k<<"\n";
    for(i=1;i<=k;i++)
        fout<<sol[i]<<"\n";
    return 0;
}