#include <iostream>
#include <fstream>
#include <cstdio>
#include <algorithm>

using namespace std;

int n, a[1005], fr[50001], maxi, nr=0, sol[1005], t=0;


int main()
{
    freopen("economie.in","r",stdin);
    freopen("economie.out","w",stdout);
    scanf("%d\n",&n);
    for (int i=0; i<n; i++)
    {
        scanf("%d\n",&a[i]);
    }
    sort(a,a+n);
    maxi=a[n-1];
    fr[0]=1;
    for (int j=0; j<n; j++)
    {
        if (fr[a[j]]==0)
        {
            nr++;
            sol[t++]=a[j];
        }
        for (int i=0; i<=maxi; i++)
        {
            if (i+a[j]<=50000&&fr[i]==1)
            {
                fr[i+a[j]]=1;
            }
        }
    }
    printf("%d\n",nr);
    for (int i=0; i<t; i++)
        printf("%d\n",sol[i]);
    return 0;
}