Visitor Entry Approval System

I live in an apartment building. Whenever someone comes to meet me, they must first

check in with the security guard at the entrance. The visitor tells the guard which

flat they want to visit. If the visitor says Flat 105, the guard clicks

a photo of the visitor and submits the request. After this, a notification is

sent to the mobile phone of the Flat 105 owner. The notification includes the visitor’s

photo and flat number. The flat owner can either Approve or Reject the request. If the owner approves

the request, the security guard receives a notification confirming approval, and the visitor

is allowed to enter. If the owner rejects the request, the guard is notified, and the visitor