#include<cstdio>
#include<cmath>
#include<algorithm>
#include<vector>

 

unsigned int v[100005], n,a[500005],c[100005],k;
void generare()
{
     unsigned int i;
	std::freopen("economie.in","r",stdin);
    std::scanf("%d",&n);
    for(i=1;i<=n;i++)
        std::scanf("%d",&v[i]);
    std::fclose(stdin);
         
}
void rezolvare()
{
     
    unsigned int i,q;
	
    std::sort(v+1,v+n+1);
     
    if(v[1]==1)
    {
        c[++k]=1;
        return ;
         
    }
        
     a[0]=1;
    for(i=1;i<=n;i++)
    {
        if(a[v[i]]==0)
           c[++k]=v[i];
  
	for(q=0;v[i]+q<=v[n];q++)
			if(a[q])
				a[v[i]+q]=1;
		
		
   	}		
    return ;
}
void afisare()
{
    unsigned int i;
	std::freopen("economie.out","w",stdout);
    std::printf("%d",k);
    std::printf("\n");
     
    for(i=1;i<=k;i++)
        {
            std::printf("%d",c[i]);
            std::printf("\n");
    }
     
    std::fclose(stdout);
}
 
int main()
{
    generare();
    rezolvare();
    afisare();
    return 0;
}