i want  activity diagram for shipping company . when app open you have to choice between 1- retailer 2- shipping company 3-freelancer.  the next step have two options  1-log in  2-sign up  .if choice sign up  you have to inseert information then back to previso page  . if choice  log in then you may be 1- retailer 2- shipping company 3-freelancer . if you  retailer  you can  make request to shipping company or freelancer. if you  shipping company or freelancer you can see requestes from retailer  and make offer for request and waite the retailer accept or reject  .app is ended  when the retailer accept or reject offer. Write your response with exactly 2 paragraphs, separated with the markdown divider: ***.
user