#include <fstream>
#include <algorithm>
using namespace std;
int n,v[1000],s[1000],si;
bool val[100001];
ifstream fin("economie.in");
ofstream fout("economie.out");
int main()
{
	int i,j;
	fin>>n;
	for(i=0;i<n;++i)
		fin>>v[i];
	sort(v,v+n);
	for(i=0;i<n;++i)
	{
		if(!val[v[i]])
			s[si++]=v[i];
		val[v[i]]=1;
		for(j=0;j<=v[n-1]-v[i];++j)
			if(val[j])
				val[j+v[i]]=1;
	}
	fout<<si<<"\n";
	for(i=0;i<si;++i)
		fout<<s[i]<<" ";
	return 0;
}