#include<stdio.h>
#include<algorithm>
using namespace std;

int v[1002],sol[1002],f[50002];

int main()
{
    freopen("economie.in","r",stdin);
    freopen("economie.out","w",stdout);
    int n,i,j,s=0,max;
    scanf("%d",&n);
    for(i=1;i<=n;++i)
        scanf("%d",&v[i]);
    sort(v+1,v+1+n);
    max=v[n];
    f[0]=1;
    for(i=1;i<=n;++i)
    {
        if(f[v[i]]==0)
        {
            sol[++s]=v[i];
            for(j=0;j<=max;++j)
                if(f[j])
                    f[j+v[i]]=1;
        }
    }
    printf("%d\n",s);
    for(i=1;i<=s;++i)
        printf("%d\n",sol[i]);
    return 0;
}