#include <fstream>
using namespace std;

ifstream f("economie.in"); ofstream g("economie.out");

int dp[50000], r[1000];
int t, i, j, n, x;

int main(){
	f>>n;
	for (i=1; i<=n; i++){
		f>>x;
		
		if (dp[x]==0) {
			t++;
			r[t]=x;
			for (j=0; j+x<=50000; j++){
				if (dp[j]==1 || j==0) dp[j+x]=1;
			}
		}
	}
	g<<t<<"\n";
	for (i=1; i<=t; i++) g<<r[i]<<"\n";
}