#include <fstream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;
ifstream cin("economie.in");
ofstream cout("economie.out");
int v[10005],d[50005],i,n,ul,pr,k,sol[10005],j;
long long S;
int main()
{
    cin>>n;
    for(i=1;i<=n;i++)
        cin>>v[i];
    sort(v+1,v+n+1);
    for(i=1;i<=n;i++)
    {
        if(d[v[i]]==0)
        {
            sol[++k]=v[i];
            d[v[i]]=1;
        }
        for(j=1;j+v[i]<=50000;j++)
            if(d[j]!=0)
              d[j+v[i]]=1;
    }
    cout<<k<<"\n";
    for(i=1;i<=k;i++)
        cout<<sol[i]<<" ";
    return 0;
}