// problema gainarului cu buncar antiatomic:D:D:D:DD:D:D:DD


#include<stdio.h>
int da,s,i,j,k,v[10000],aux,n;
FILE *in,*out;
void main()
{
 in=fopen("oo.in","rt");
 out=fopen("oo.out","wt");
 fscanf(in,"%d",&n);
 for(i=0;i<n;i++)
  fscanf(in,"%d",&v[i]);


 aux=v[0]+v[n-1];
 for(i=0;i<n-1;i++)
  v[i]=v[i]+v[i+1];
 v[n-1]=aux;
 k=n;
 da=1;
 while(k>=i && da==1)
 {

  da=0;
  for(i=1;i<k;i++)
  {

   aux=v[0];
   if(v[i]>=aux)
   {
    aux=v[i];
    j=i;
    da=1;
   }
   if(da)
   {
    v[j+1]=v[k-1];
    v[j-1]=v[k-2];
    v[k-1]=v[k-2]=0;
    k=k-2;
    v[j]=0;
    da=1;
    s+=aux;
   }
  }



 }
 fprintf(out,"%d",s);
}