#include <bits/stdc++.h>
#define MAXN 1000
#define MAXX 50000

using namespace std;

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

int main() {
    int n, arr[MAXN];
    vector<int> solutii;
    bitset<MAXX> c;
    fin >> n;
    for (int i = 0; i < n; i++)
        fin >> arr[i];
    sort(arr, arr + n);
    int maxi = arr[n - 1];
    c[0] = 1;
    for (int i = 0; i < n; i++) {
        if (c[arr[i]])
            continue;
        solutii.push_back(arr[i]);
        c[arr[i]] = 1;
        for (int j = 0; j + arr[i] <= maxi; j++)
            if (c[j])
                c[arr[i] + j] = 1;
    }

    fout << solutii.size() << '\n';
    for (auto &solutie: solutii)
        fout << solutie << ' ';
    return 0;
}