#include <iostream>
#include <algorithm>
#include <fstream>
#include <cmath>
using namespace std;

ifstream f("economie.in");
ofstream g("economie.out");

int n,v[1005],dr[1005],nr=0,tr=0,maxim;
bool ghiozdan[50005];

int main()
{
f>>n;
for(int i=1;i<=n;i++)
  f>>v[i];
sort(v+1,v+n+1);
maxim=v[n];
bool OK=0;
for(int i=1;i<=n;i++)
 {
  if(ghiozdan[v[i]]==0)
   {
    nr++;
    dr[nr]=v[i];
    ghiozdan[v[i]]=1;
    for(int j=1;j<=maxim-v[i];j++)
    if(ghiozdan[j+v[i]]==1)
    ghiozdan[j]=ghiozdan[j+v[i]];
    OK=0;
   }
 }
g<<nr;
for(int i=1;i<=nr;i++)
 g<<endl<<dr[i];
}