Suppose there are exactly two packet switches between a sending host and a receiving host. The transmission rate between the sending host and switch#1 is R1. The transmissions rate between switch#1 and switch#2 and between switch#2 and the receiving host are R2 and R3, respectively. Assuming that the switches user 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.)