Four identical servers have been installed to support a company's computer network. Two servers are physically located in one building and the other two are located in a different building. The time to server failure has a Lognormal distribution with the mean of 2817 hours and σ=0.49. The servers undergo maintenance every 1115 hours. Support is to be provided over the 1115 hour operating period. What is the probability of successful network support if the network can function with a minimum of any two servers?