#include <iostream>
#include <fstream>
#include <algorithm>
#include <fstream>
#define MAX 50002
using namespace std;
int n,v[MAX],dp[MAX],w[MAX],k,elem;

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

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++){
        fin >> v[i];
        elem = max(elem, v[i]);
    }
    sort(v+1, v+n+1);
    for(int i = 1; i <= n; i++){
        if(dp[v[i]] == 0){
            w[++k] = v[i];
            dp[v[i]] = 1;
            for(int j = 1; j <= elem-v[i]; j++){
                if(dp[j] != 0){
                    dp[j+v[i]] = 1;
                }
            }
        }
    }
    dp[0] = 0;
    fout << k << "\n";
    for(int i = 1; i <= k; i++){
        fout << w[i] << " ";
    }
    return 0;
}