Customers arrive at a two$-$server system at a Poisson rate $\backslash$lambda $.$ An arrival finding the system empty is equally

likely to enter service with either server. An arrival finding one customer in the system will enter service

with the idle server. An arrival finding two others in the system will wait in line for the first free server. An

arrival finding three in the system will not enter. All service times are exponential with rate $,$ and once a

customer is served $($by either server$),$ he departs the system.