program nunta;
var f,g:Text;
    n,y,cont,i:longint;
begin
assign(f,'nunta.in');
assign(g,'nunta.out');
reset(f);
rewrite(g);
read(f,n);
cont:=n;
if (n div 2>=2)then
  for i:=1 to n-3 do cont:=cont+i;
for y:=3 to n div 2 do
  begin
    for i:=1 to n-(2*y-1) do
      cont:=cont+(i*(i+1)div 2);
  end;
write(g,cont);
close(f);
close(g);
end.