ABC Incorporated wants to implement a TCP/IP network for its only site. It has 180 employees and two buildings and requires Internet access for an e-mail server, a single Web server, a single FTP server, and two routers, each with a single high-speed Internet interface. If the company wants to hold ISP costs to a minimum, what kinds of IP addresses should it primarily use? What is the smallest block of public IP addresses that the company can purchase to cover its needs?