title: Simplify an activity diagram
body: <p>I'm working on my graduation project which is an online quiz website. now i'm drawing the UML activity diagram but it gets too complex and i can't add more details because at the end it must be printed in the project documentation in A4 papers.<br>
  can i split the diagram into multiple diagrams?. and if i did this should i repeat the login/registration actions in the beginning of each diagram?
  <br>
  <a href="https://i.stack.imgur.com/MD9i1.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MD9i1.jpg" alt="enter image description here"></a></p>