#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");

int v[1001], sol[1001], f[50001];

int main()
{
    int n, i, nr=0, j;
    i=1;
    while(fin>>v[i])
    {
        i++;
    }
    i--;
    n=i;
    sort(v+1, v+n+1);
    for(i=1;i<=n;i++)
    {
        if(f[v[i]]==0)
        {
            nr++;
            sol[nr]=v[i];
            //f[v[i]]=1;
            for(j=1;j+v[i]<=v[n];j++)
            {
                if(f[j]==1)
                {
                    f[j+v[i]]=1;
                }
            }
        }
    }
    fout<<nr<<"\n";
    for(i=1;i<=nr;i++)
    {
        fout<<sol[i]<<"\n";
    }
}