Create a set of use cases for the following high-level requirements in a housing system run by the Campus Housing Service. The Campus Housing Service helps students find apartments. Owners of apartments fill in information forms about the rental units they have available (e. g. locaiton, number of bedrooms, monthly rent), which are tnered into a database. Students can search through this database via the Web to find aprtments that meet their needs (e. g., a two-bedroom apartment for $800 or less per month with 1/2 mile of coampus). They then contract the aprtment owners directly to see the aprtment and possibly rent it. Apartment owners call the service to delete their listing when they have rented their aparmtnet(s). In the building the major use cases, follow the four-step process: identify the use cases, identify the steps within them, identify the elements within the steps, and confirm the use cases.