Any memory leak (or excessive creation of objects) when using the iOS Storyboard Seque “Model” or “Push” styles?

Let's say I'm developing a simple iPhone application with two screens: login and registration screens. On the "Login" screen, he has a "Register" button, which goes to the "Register" screen. Similarly, on the "Register" screen, it has a "Login" button, which goes to the "Login" screen. Everything is implemented using the iOS Storyboard Segue Modal style.

Question: Does it constantly add a new view to the stack every time a view controller is represented by the "Modal" style? So, if I switch again between the Login and Register screens, will it each time create new objects and accumulate them using the container of the internal array (for example, stack)?

Also, if I changed the style to “push,” how would the situation look like a similar question? Doesn't push continue to add new viewers to the top of the page every time it is pushed?