SESSION being lost after MySQLi Log In User. How to maintain SESSION value?

I have a page that, when the user is signed in, saves a value (integer) in session once a user has selected it from a drop down menu on a previous page.

<?php
@session_start();
if("" == "")     {
  $_SESSION["tics"] = "".(isset($_POST['numberoftickets'])?$_POST['numberoftickets']:"")  ."";
}
?>

If they're not signed in then the user is presented with a MySQLi Log In User form, on the same page. However, when they sign in the session value is lost.
I assumed this was because, on sign in, we're no longer posting the form value "'numberoftickets'" so I added "'numberoftickets'" as a hidden form field on the sign in form and that's not working either. :(

Urrgh. When a client insists on it working a particular way and it's just plain the wrong way to do things. My suggestion was to make the user sign in before you ask them to make a selection. No. No way. Jeez! :(

How do I retain the original form submission value throughout this process?

Also, what if the user isn't registered. How will I retain this form submission throughout the entire register, confirm etc?

Appreciate any advice offered.
Thank you.
NJ

Syntax errors with that?

Maybe the missing space after the if? I've updated the code.

Still a syntax error with that? See attached.

Seems like dreamweaver might be making a mistake, or maybe code above is in conflict somehow. When I paste the code into CC 2017 it doesn't show a syntax error.

It's crashing the whole page:
http://www.dreamcaruk.com/spot-the-ball-win-a-car.php?dcID=4

EDIT: Doesn't matter where I place the code on the page. The syntax error remains and the page doesn't load on the server.

Some sort of weird corruption in the space character. I re-typed the spaces around the = and it fixed the problem.