A customer is considering implementing an EMC Disk Library with Active Engine Failover (AEF). Front-end ports 1, 3, and 4 from Engine A will be connected to the SAN. On Engine B, front-end ports 7, 8, and 11 will be connected to the SAN.

To ensure proper AEF functionality, what is the total number of front-end ports from both engines that need to be connected to the SAN?