{$APPTYPE CONSOLE}
var f:text;i,j,n,s,t:integer;
a:array[1..10000] of integer;
begin
assign(f,'Discount.dat');reset(f);
readln(f,n);
for i:=1 to n do
read(f,a[i]);close(f);
for i:=2 to n do
for j:=n downto i do begin
if a[j-1]<a[j] then begin
t:=a[j];
a[j]:=a[j-1];
a[j-1]:=t;
end;end;
if n>=3 then begin
i:=3;
while i<=n do begin
a[i]:=0;i:=i+3;end;
end;
s:=0;
for i:=1 to n do
s:=s+a[i];
assign(f,'Discount.sol');rewrite(f);
writeln(f,s);close(f);
end.