#include <bits/stdc++.h>

using namespace std;
int v[1005];
int f[50005];
vector <int> monede;
int main()
{
    ifstream cin ("economie.in");
    ofstream cout ("economie.out");
    int n,i,j;
    cin>>n;
    for(i=1; i<=n; i++)
    {
        cin>>v[i];
    }
    sort(v+1,v+n+1);
    int maxx=v[n];
    for(i=1; i<=n; i++)
    {
        if(f[v[i]]==0)
        {
            monede.push_back(v[i]);
            f[v[i]]=1;
            for(j=1; j<=maxx-v[i]; j++)
            {
                if(f[j]==1)
                {
                    f[j+v[i]]=1;
                }
            }
        }
    }
    cout<<monede.size()<<"\n";
    for(i=0;i<monede.size();i++)
        cout<<monede[i]<<"\n";


    return 0;
}