#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
const int Nmax=1005;
int v[Nmax],sol[Nmax];
int f[50005];
int main()
{
    int n,x;
    fin>>n;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
    }
    sort(v+1,v+n+1);
    if (v[1]==1)
    {
        fout<<1<<'\n'<<1;
        return 0;
    }
    int cnt=0;
    for(int i=1;i<=n;i++)
    {
        if(f[v[i]]==0)
        {
            cnt++;
            sol[cnt]=v[i];
            int p=1;
            while(p*v[i]<=v[n])
            {
                f[p*v[i]]=1;
                for(int j=1;j<=cnt;j++)
                {
                    int p2=1;
                    while(p2*sol[j]<=v[n]-p*v[i])
                    {
                        f[p*v[i]+p2*sol[j]]=1;
                        p2++;
                    }
                }
                p++;
            }
        }
    }
    fout<<cnt<<'\n';
    for(int i=1;i<=cnt;i++)
    {
        fout<<sol[i]<<'\n';
    }
    return 0;
}