#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
int n,i,j,a[1005],s[50505],sol[1005],nr;
int main()
{
    ifstream cin ("economie.in");
    ofstream cout ("economie.out");
    cin>>n;
    for(i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    sort(a+1,a+n+1);

    for(i=1;i<=n;i++)
    {
        if(s[a[i]]==0)
        {
            nr++;
            sol[nr]=a[i];
            s[a[i]]=1;
            for(j=0;j<=50000;j++)
            {
                if(s[j]==1)
                    s[j+a[i]]=1;
            }
        }
    }
    cout<<nr<<'\n';
    for(i=1;i<=nr;i++)
        cout<<sol[i]<<'\n';
    return 0;
}