#include <bits/stdc++.h>
using namespace std;

ifstream ci("economie.in");
ofstream cou("economie.out");

int n,v[1005];
int f[50005];
int sol[1005];
int p;

void citire(){
    ci>>n;
    for(int i=1;i<=n;i++){
        ci>>v[i];
    }
    sort(v+1,v+n+1);
}

void rez(){
   int i,s=0;
   for(i=1;i<=n;i++){
        if(f[v[i]]==0){
            sol[++p]=v[i];
            s=0;
            f[v[i]]=1;
            for(int j=1;j<=50000-v[i];j++){
                if(f[j]==1){
                    f[j+v[i]]=1;
                }
            }
        }
   }
   cou<<p<<"\n";
   for(i=1;i<=p;i++){
        cou<<sol[i]<<"\n";
   }
}

int main()
{
    citire();
    rez();
    return 0;
}