//ECONOMIE INFOARENA

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

#define NMAX 1002
#define VMAX 50004

ifstream fin("economie.in");
ofstream fout("economie.out");
int NR[VMAX];

int main()
{
	NR[0]=1;
	int n,A[NMAX];
	int i,j;
	fin>>n;
	for (i=1;i<=n;i++)
	{
		fin>>A[i];
	}
	sort(A+1,A+n+1);
	for (i=1;i<=n;i++)
	{
		for (j=1;j<=VMAX;j++)
			if (NR[j-A[i]]==1)
				NR[j]++;

	}
	int max=0;
	for (i=1;i<=n;i++)
		if (NR[A[i]]==1)
			max++;
	fout<<max<<'\n';
	for (i=1;i<=n;i++)
		if (NR[A[i]]==1)
			fout<<A[i]<<'\n';
	fout.close();
	return 0;
}