#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 1003, valMAX = 50003;
int w[NMAX], minim, rest[valMAX], nrRest, maxim;
bool ok[valMAX];
int main()
{
    int n, i;
    fin >> n;
    minim = INT_MAX;
    maxim = INT_MIN;
    for(i = 1; i <= n; ++i)
        fin >> w[i], minim = min(minim, w[i]), maxim = max(maxim, w[i]);

    sort(w+1, w+1+n);
    rest[0] = minim;
    nrRest = 1;

    int j;
    ok[0] = true;
    for(i = 1; i <= n; ++i){
        if(rest[w[i] % minim])
            continue;

        ++nrRest;
        rest[w[i] % minim] = w[i];
        ok[w[i] % minim] = true;

        for(j = 1; j < minim; ++j){
            if(j == w[i] % minim)
                continue;

            if(rest[j] && rest[(j+w[i])%minim] == 0)
                 rest[(j+w[i])%minim] = -1;
        }
    }

    fout << nrRest << '\n';

    for(i = 0; i < minim; ++i)
        if(ok[i])
            fout << rest[i] << ' ';


    return 0;
}