#include <bits/stdc++.h>

using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");

int cnt,v[1005],maxim,n,rasp,aux[1005];
bool apar[50005];

int main()
{
    fin>>n;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
        maxim=max(maxim,v[i]);
    }
    sort(v+1,v+n+1);
    for(int i=1;i<=n;i++)
    {
        if(apar[v[i]]==0)
        {
            rasp++;
            aux[rasp]=v[i];
            apar[v[i]]=0;
            for(int j=1;j<=maxim-v[i];j++)
            {
                if(apar[j]==1)
                {
                    apar[j+v[i]]=1;
                }
            }
        }
    }
    fout<<rasp<<endl;
    for(int i=1;i<=rasp;i++)
        fout<<aux[i]<<endl;
}