#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
int N,v[1001];
int dp[50001]; //notez daca pot forma suma i folosind monedele deja alese
int sol[1001],nr;
int main()
{
    fin>>N;
    for(int i=1;i<=N;i++)
        fin>>v[i];
    sort(v+1,v+N+1);
    dp[0]=1;
    for(int i=1;i<=N;i++){
        if(dp[v[i]]==0){
            sol[++nr]=v[i];
            for(int j=v[i];j<=50000;j++)
                if(dp[j-v[i]]==1)
                    dp[j]=1;
        }
    }
    fout<<nr<<endl;
    for(int i=1;i<=nr;i++)
        fout<<sol[i]<<" ";
    return 0;
}