program exemplo1

	var
		n, s, i: integer;
	procedure soma;
		var q: integer;
	begin
		q:=i*i;
		if (i div 2)*2 = i then
			s:=s+q;
		else
			s:=s-q;
	end;
begin
	read(n);
	s:=0; i:=0;
	while i<=n do
	begin	
		soma;
		write (s);
		i:=i+1; 
	end
end.