Suppose there is exactly one packet switch between a sending host and a receiving host.

Suppose there is exactly one packet switch between a sending host and a receiving host. The transmission rate between the sending host and the switch and between the switch and the receiving host are R1 and R2, respectively. Assuming that the switch uses store-and-forward packet switching, what is the total end-to-end delay to send a packet of length L? (Ignore queuing, propagation delay, and processing delay.)