#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin("economie.in");
ofstream fout("economie.out");

const int DIM = 1010;
const int MAX = 50010;

int n;
int v[DIM];
bool visited[MAX], isSol[MAX];

int main() {
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> v[i];

    sort(v + 1, v + n + 1);

    int solCnt = 0;
    visited[0] = true;
    for (int i = 1; i <= n; i++) {
        bool hasVisited = false;
        for (int j = i; j <= n; j++) {
            if (visited[v[j] % v[i]] && !visited[v[j]])
                visited[v[j]] = hasVisited = true;
        }
        if (hasVisited) {
            solCnt++;
            isSol[i] = true;
        }
    }

    fout << solCnt << '\n';
    for (int i = 1; i <= n; i++)
        if (isSol[i])
            fout << v[i] << ' ';

    return 0;
}