A peer-to-peer system consists of a server (containing a copy of a file), and 20 peers. The file size is 10,000 bits, the upload rate of the server is 5,000 bits/sec., and the upload rate of each peer is 2,500 bits/sec. The download rate of each peer is 4,000 bits/sec. What is the minimum time required to distribute the file to all the peers under the peer-to-peer model.