#include<fstream>
#include<algorithm>

using namespace std;

ifstream fin("economie.in");
ofstream fout("economie.out");

int n,v[1005],sol[1005],k;
bool use[50005];

int main()
{
	fin>>n;
	for(int i=1;i<=n;i++)
		fin>>v[i];
	sort(v+1,v+n+1);
	for(int i=1;i<=n;i++)
	{
		if(use[v[i]])
			continue;
		use[v[i]]=1;
		for(int j=1;j<=50000-v[i];j++)
			if(use[j])
				use[j+v[i]]=1;
		sol[++k]=v[i];
	}
	fout<<k<<"\n";
	for(int i=1;i<=k;i++)
		fout<<sol[i]<<"\n";
	return 0;
}