#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]<<" ";
}