#include<stdio.h>
#include<algorithm>
using namespace std;
FILE *fin, *fout;
int n,i,j,v[1001],nr[50001],w[1001],k;

int main(){

    fin=fopen("economie.in","r");
    fout=fopen("economie.out","w");

    fscanf(fin,"%d",&n);

    for(i=1;i<=n;i++){
        fscanf(fin,"%d",&v[i]);
    }
    sort(v+1,v+n+1);
    nr[0]=1;
    for(i=1;i<=n;i++){
        if(nr[v[i]]==0){
            w[++k]=v[i];
            for(j=0;j<=v[n]-v[i];j++){
                if(nr[j]!=0){
                    nr[j+v[i]]=1;
                }
            }
        }
    }

    fprintf(fout,"%d\n",k);
    for(i=1;i<=k;i++){
        fprintf(fout,"%d ",w[i]);
    }

    fclose(fout);
    fclose(fin);

return 0;
}