A traveller login to the Smart Travel website by using his$/$her customer$$s name and password. He$/$she inputs a date, from location and to location to search flights. Once the traveller finds a flight, he$/$she clicks the button to book an air ticket. He$/$she inputs payment details and then clicks the confirm button. The Smart Travel server receives the booking details and verifies the payment. If the payment is valid, the server generates an air ticket and a receipt, then sends them to the traveller. Use the software tool UMLet to specify this process in a UML System Sequence Diagram. The diagram must show the sequence of messages between an actor and the system.