Write a program in Python that computes the fuel efficiency of a multi-leg journey with the following criteria.

Prompt for the starting odometer reading.

Get information about a series of legs.

For each leg, the user enters the current odometer reading and the amount of gas used (separate by a space).

The user signals the end of the trip with a blank line.

The program should print or display the miles per gallon (MPG) achieved on each leg and the total MPG for the trip.