#include<fstream>
#include<algorithm>
using namespace std;
ifstream f("economie.in"); ofstream g("economie.out");
int n,amax,nr,a[1001],sel[1001],x[50001];
int main()
{   f>>n;
	int i,j;
    for(i=1; i<=n; i++)
	{   f>>a[i];
        if(amax<a[i]) amax=a[i];
    }
    sort(a+1,a+n+1);
    x[0]=1;
    for(i=1;i<=n;++i)
		if(!x[a[i]])
		{   sel[++nr]=a[i];
			for(j=0;j+a[i]<=amax;++j)
				if(x[j]) x[j+a[i]]=1;
        }
    g<<nr<<"\n";
    for(i=1;i<=nr;i++) g<<sel[i]<<"\n";
	g.close(); return 0;
}