#include <fstream>
#include <vector>
#include <algorithm>
#define max_val 50000
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");

int v[1005];

int n;

bool c[max_val+5];

vector <int> sol;

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(!c[v[i]])
            sol.push_back(v[i]);
        c[v[i]]=true;
        for(int j=1;j + v[i]<=max_val;j++)
            if(c[j])
                c[j + v[i]]=true;
    }
    fout<<int(sol.size())<<'\n';
    for(auto& i : sol)
        fout<<i<< ' ';
}