#include <fstream>
#include <climits>
#include <algorithm>
#include <vector>
#include <cstring>
#define DIM 50001
using namespace std;

ifstream cin("economie.in");
ofstream cout("economie.out");

// declaring
int d[DIM],n,v[1005],nr,sol[DIM],k=0;

   int main()
   {
      ////reading
     cin >> n;
     for (int i=0;i<n;i++){
      cin >> v[i];
     }
     nr=n;
       
      ////sort after value 
      sort(v,v+n);

      d[0]=1;
      ////algorithm
     for (int i=0;i<n;i++){
      if (d[v[i]]==0){
         sol[k]=v[i];///we add it if we cant make it from the smaller nrs
         k++;
      
      for (int j=0;j<=v[n-1];j++){
         if (v[i]+j<=v[n-1]&&d[j]!=0){
            d[v[i]+j]=1;
             
         }
      }
     }}
   
      ////outputting
      

      // test
     /*for (int i=0;i<n;i++){
      cout << v[i] << " ";
     }
     cout << endl;
     for (int i=0;i<=v[n-1];i++){
      cout <<i<<"//"<< d[i] << " ";
     }*/
     cout << k<<endl;
     for (int i=0;i<k;i++){
      cout <<sol[i] << " ";
     }
     }