Consider such flux tubes that connect the two magnets and are in the form of solids of rotation. As a first step towards the solution, you need to work out, how they are transformed when the distance between the magnets is increased.
Please submit the solution to this problem via e-mail to physcs.cup@gmail.com. The next hint for the Problem 3 will be published at 13:00 GMT, 26th February 2023, together with the next updates of the intermediate results.