#include <fstream>
using namespace std;
int m,i,j,n,v[1005],x[1005],b[50005],a[50005],k,l,ok;

ifstream f ("economie.in");
ofstream g ("economie.out");
int main (){
	
	f>>n;
	for(i=1;i<=n;i++)
	
		f>>v[i];
	
	sort(v+1,v+n+1);

	
	k=0;
	a[0]=1;
	for (i=1;i<=n;i++)
	{
		if (!a[v[i]])
		{
			k++;
			x[k]=v[i];
			for (j=v[i];j<=v[n];j++)
				if (a[j-v[i]])
					a[j]=1;
		}
	}
	

	g<<k<<endl;
	for(i=1;i<=k;i++)
		g<<x[i]<<endl;





return 0;
}