#include<cstdio>
#include<algorithm>
#include<vector>
using namespace std;
int a[1005];
bool d[50005];
int main()
{
    freopen("economie.in","r",stdin);
    freopen("economie.out","w",stdout);
    int n;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        scanf("%d",a+i);
    sort(a+1,a+n+1);
    vector<int> sol;
    d[0]=1;
    for(int i=1;i<=n;i++)
        if(!d[a[i]])
        {
            sol.push_back(a[i]);
            for(int j=0;j<=a[n]-a[i];j++)
                if(d[j])
                    d[j+a[i]]=1;
        }
    printf("%d\n",(int)sol.size());
    for(int i=0;i<(int)sol.size();i++)
        printf("%d%c",sol[i],i==(int)sol.size()-1?'\n':' ');
    return 0;
}