#include<fstream>
#include<algorithm>
using namespace std;
ifstream in("economie.in");
ofstream out("economie.out");
int n,x,l, a[1009],sol[1009];
bool v[50009];
int main()
{
    in>>n;
    for(int i=1;i<=n;i++)
        in>>a[i];
    sort(a+1,a+n+1);
    v[0]=1;
    for(int i=1;i<=n;i++)
    {
        if(!v[a[i]])
        {
            sol[++l]=a[i];
            v[a[i]]=1;
            for(int k=0;k<=50000;k+=a[i])
                v[k]=1;
            for(int k=0;k<=50000;k++)
                if(v[k]) v[k+a[i]]=1;

        }
    }
    out<<l<<'\n';
    for(int i=1;i<=l;i++)
            out<<sol[i]<<'\n';
    out.close();
    return 0;
}