#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin ("economie.in");
ofstream fout("economie.out");
int V[1005],n,i,j,sol[1001],k;
bool F[50005];
int main()
{
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>V[i];
    sort(V+1,V+n+1);
    for(i=1;i<=n;i++)
    {
        if(!F[V[i]])
            sol[++k]=V[i];
        F[V[i]]=1;
        for(j=1;j+V[i]<=50000;j++)
            if(F[j])
                F[j+V[i]]=1;
    }
    fout<<k<<"\n";
    for(i=1;i<=k;i++)
        fout<<sol[i]<<" ";
    return 0;
}