System sperifications lasing llie given propesitions and logical connetives $($including nega$-$

p$.$ The user entery an valid password

$$: Accoss is granted

or$.$ The use las paid the sibseription fee

A paid the subscription fee, but does not enter a valid password.

nted whenever the nser has paid the subscription fee and enters a valid pasword.

ied if the user las not paid the subseription foo$-$

tions$).$

p: The user entors an valid passworl

q: Access is granted

r: The user has paid the subseription fee

$($a$)$ The user has paid the subseription fee, but does not enter at valid password,

$($b$)$ Access is granted whenever the user las paid the subscription fee and enters a valid password.

$($c$)$ Access is denied if the user lias not paid the subseription fee: