var n, i, res: integer;
begin
  res:=1;
  readln(n);
  if n mod 2 = 0 then
    for i:=1 to n div 2 do
      res:=res*i*2
   else
    for i:=0 to n div 2 do
      res:=res*(i*2+1);
  writeln(res);
end.