#include<fstream>
#include<vector>
#include<algorithm>
using namespace std;
int n,a[1001],i,j,m;
bool uz[50001];
vector<int> v;
int main()
{

    ifstream f("economie.in");
    ofstream g("economie.out");
    f>>n;
    for(i=1;i<=n;++i)
    {
       f>>a[i];
       if(a[i]>m)
       m=a[i];
    }
    sort(a+1,a+n+1);
    uz[0]=1;
    for(i=1;i<=n;++i)
    if(!uz[a[i]])
    {
        v.push_back(a[i]);
        for(j=a[i];j<=m;++j)
           if(uz[j-a[i]])
             uz[j]=1;
    }


    g<<v.size()<<"\n";
    for(i=0;i<v.size();++i)
    g<<v[i]<<"\n";
    return 0;
}