#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, nrRest, maxim, sol[NMAX], nrSol;
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);

    for(i = 1; i <= n; ++i){
        ///daca pot forma suma
        if(ok[w[i]])
            continue;

        sol[++nrSol] = w[i];
        ok[w[i]] = true;

        int j;
        for(j = 0; j + w[i] < valMAX; ++j)
            if(ok[j])
                ok[j + w[i]] = true;
    }

    fout << nrSol << '\n';

    for(i = 1; i <= nrSol; ++i)
        fout << sol[i] << ' ';


    return 0;
}