//ECONOMIE INFOARENA

#include <fstream.h>

#define NMAX 1002
#define VMAX 5004

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];
		for (j=A[i];j<=VMAX;j++)
			if (NR[j-A[i]]!=0)
				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;
}