Suppose you are working for a fast-growing startup company, which we will call FastCo, and it is your job to write a software package that can maintain the set, E, of all the employees working for FastCo. In particular, your software has to maintain, for each employee, x in E, the vital information about x, such as his or her name and address, as well as the number of shares of stock in FastCo that the CEO has promised to x. When an employee rst joins FastCo they start out with 0 shares of stock. Every Friday afternoon, the CEO hosts a party for all the FastCo employees and kicks things off by promising every employee that they are getting y more shares of stock, where the value of y tends to be different every Friday. Describe how to implement this software so that it can simultaneously achieve the following goals