#include <fstream>
#include <cstring>
#include <algorithm>
using namespace std;
ifstream cin("economie.in");
ofstream cout("economie.out");
int dp[50001],v[1001],sol[1001],n,i,j,k;
int main()
{
    cin>>n;
    for(i=1;i<=n;i++)
        cin>>v[i];
    sort(v+1,v+n+1);
    memset(dp,-1,sizeof(dp));
    dp[0]=0;
    for(i=1;i<=n;i++)
    {
        if(dp[v[i]]==-1)/// submultimea nu a fost formata
        {
            sol[++k]=v[i];
            for(j=0;j<=v[n]-v[i];j++)///det alte monezi la care putem adauga moneda actuala
                if(dp[j]!=-1)   /// s-a obtinut anterior submultimea de suma j
                    dp[j+v[i]]=1;   /// obtin submultimea de suma j+v[i]
        }
    }
    cout<<k<<'\n';
    for(i=1;i<=k;i++)
        cout<<sol[i]<<'\n';
    return 0;
}