A chemical manufacturer wishes to store chemicals in a warehouse. Some chemicals react violently when in contact with each other, and the manufacturer decides to divide the warehouse into a number of areas so as to separate dangerous pairs of chemicals. In the following table, an asterisk indicates those pairs of chemicals that must be kept apart.[br][b][color=#073763] [br]What is the smallest number of areas needed to store these chemicals safely?[br][/color][/b]