#include<algorithm>
#include<cstdio>
using namespace std;
int dp[50010],n,i,j,v[1010],nr;
bool b[1010],x[50010];
int main()
{
    freopen("economie.in","r",stdin);
    freopen("economie.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++) scanf("%d",&v[i]),x[v[i]]=1;
    sort(v+1,v+n+1);
    for(i=1;i<=v[n];i++)
    {
        for(j=1;j<=n;j++)
        {
            if(i==v[j]) dp[i]=j;
            if(i>v[j]) if(dp[i-v[j]]) dp[i]=j;
            if(dp[i]) break;
        }
        if(!x[i]) continue;
        if(b[dp[i]]) continue;
        b[dp[i]]=1; nr++;
    }
    printf("%d\n",nr);
    for(i=1;i<=n;i++) if(b[i]) printf("%d ",v[i]);
    return 0;
}