program ex;
type
 ss=array[1..10000]of integer;
var
 a:ss;
 max:longint;
 f1,f2:text;
 n:integer;
 flag:boolean;
procedure init;
 var
  i:integer;
 begin
  assign(f1,'fruit.in');
  assign(f2,'fruit.out');
  reset(f1);
  rewrite(f2);
  readln(f1,n);
  for i:=1 to n do read(f1,a[i]);
  for i:=2 to n do
   if a[i]<a[i-1] then flag:=true;
 end;
procedure quick(l,r:integer);
 var
  i,j,x,y:integer;
 begin
  i:=l;
  j:=r;
  x:=a[(i+r)div 2];
  repeat
   while a[i]<x do inc(i);
   while a[i]>x do dec(j);
   if i<=j then
    begin
     y:=a[i];
     a[i]:=a[j];
     a[j]:=y;
     inc(i);
     dec(j);
    end;
  until i>j;
  if l<j then quick(l,j);
  if i<r then quick(i,r);
 end;
procedure main;
 var
  m,i,j,t,x:integer;
 begin
  t:=n;
  i:=0;
  repeat
   j:=0;
   x:=0;
   m:=0;
   inc(i);
   if a[i]<>0 then
    begin
     x:=a[i]+a[i+1];
     a[i]:=0;
     a[i+1]:=0;
     dec(t);
     max:=max+x;
    end;
   if t=1 then exit;
   m:=i+1;
   j:=i;
   while x>a[j] do inc(j);
   dec(j);
   for i:=j downto m do
    a[i-1]:=a[i];
   a[j]:=x;
   dec(i);
  until t=1;
 end;
begin
 init;
 if flag=true then quick(1,n);
 max:=0;
 main;
 writeln(f2,max);
 close(f1);
 close(f2);
end.