#include<fstream>
using namespace std;
ifstream f("economie.in");
ofstream g("economie.out");
int n,m,i,j,a[1001],uz[5001],nr,sol[1001],aux;
int main()
{
    f>>n;
    for(i=1;i<=n;i++)
    f>>a[i];
    for(i=1;i<=n-1;i++)
    for(j=i+1;j<=n;j++)
    if(a[i]>a[j])
    {
        aux=a[i];
        a[i]=a[j];
        a[j]=aux;
    }
    m=a[n];
    uz[0]=1;
    for(i=1;i<=n;i++)
    if(!uz[a[i]])
    {
        for(j=1;j<=m;j++)
        if(a[i]<=j&&uz[j-a[i]]==1)
            uz[j]=1;
        sol[++nr]=a[i];
    }
    g<<nr<<"\n";
    for(i=1;i<=nr;i++)
    g<<sol[i]<<"\n";
}