#include <iostream>

using namespace std;

int main()
{

    return 0;
}#include <iostream>

#include <algorithm>

#include <fstream>

#include <vector>

using namespace std;

ifstream fin("economie.in");

ofstream fout("economie.out");

bool d[50004];

int v[1002];

int n,i,j,maxx;

vector <int> sol;

int main()

{

 fin>>n;

 for(i=1;i<=n;i++)

 {

     fin>>v[i];

     maxx=max(maxx,v[i]);

 }

 sort(v+1,v+n+1);

 for(int i=1;i<=n;i++)

  if(d[v[i]]==0)

 {

     sol.push_back(v[i]);

     d[v[i]]=1;

     for(int j=0;j<=maxx-v[i];j++)

        if(d[j]==1)

           d[j+v[i]]=1;

 }

 fout<<sol.size()<<"\n";

 for(j=0;j<sol.size();j++)

    fout<<sol[j]<<" ";

}