#include <iostream>
#include <fstream>
#include<algorithm>
using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
int dp[50001],v[1001],sol[1001];
int main()
{ ///ECONOMIE infoarena
    int n,k=0;
    fin>>n;
    for(int i=1;i<=n;i++){
        fin>>v[i];
    }
    sort(v+1,v+n+1);
    for(int i=1;i<=n;i++){
        dp[i]=-1;
    }
    for(int i=1;i<=n;i++){
        if(dp[v[i]]==-1){ ///submultimea nu a fost formata
            sol[k++]=v[i];    /// selectez elementul
            for(int j=0;j<=v[n]-v[i];j++){   /// j= suma unei posibile submultimi obtinute anterior
                if(dp[j]!=-1){ ///s a obt anterior submultimea de suma j
                    dp[j+v[i]]=1; ///obt submultimea de suma j+v[i]
                }
            }
        }
    }
    fout<<k<<"\n";
    for(int i=1;i<=k;i++){
        fout<<sol[i]<<"\n";
    }
    return 0;
}