{
task2.pas
Copyright 2009 Martin Habovštiak
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
}
program task2;
var i,sum,n : cardinal;
BEGIN
readln(n);
sum:=0;
for i:=1 to n do sum := sum+ i*(i+1) div 2 + i*(i+1);
writeln(sum);
END.