#include <bits/stdc++.h>
#define NUM 50005
using namespace std;
bitset <NUM> c;
vector <int> sol;
int v[1005];
int n;
ifstream f("economie.in");
ofstream g("economie.out");
int main()
{
    f >> n;
    for(int i = 1; i <= n; ++i)
    {
        f >> v[i];
        if(!c[v[i]])
        {
            c[v[i]] = 1;
            sol.push_back(v[i]);
            for(int j = 1; j < NUM - v[i]; ++j)
                if(c[j])
                    c[j + v[i]] = 1;
        }
    }
    g << sol.size() << '\n';
    for(int i = 0; i < sol.size(); ++i)
        g << sol[i] << '\n';
}