#include <fstream>
#include <algorithm>
using namespace std;
int n, a[50002], m = 1;
short v[50002];
ifstream f("economie.in");
ofstream g("economie.out");
int main()
{
    f >> n;
    for(int i = 1; i <= n; i++) f >> a[i];
    sort(a + 1, a + n + 1);
    v[a[1]] = 2;
    for(int i = 2 * a[1]; i <= a[n]; i+= a[1])
        v[i] = 1;
    for(int i = 2; i < n; i++){
        if(v[a[i]] == 0){
        v[a[i]] = 2;
         m++;
        for(int j = a[1]; j <= a[n] - a[i]; j++)
            if(v[j] != 0 && v[j + a[i]] == 0) v[j + a[i]] = 1;
    }
    }
    g << m << "\n";
    for(int i = 1; i <= n; i++)
        if(v[a[i]] == 2) {
        g << a[i] << "\n";
        v[a[i]] = 1;
        }

    return 0;
}