Find out the number of routes with the greatest number of flights (trips).
- A - B and B - A are to be considered DIFFERENT routes.
- Use the Trip table only.
Trip(trip_no, id_comp, plane, town_from, town_to, time_out, time_in).
ADVICE:- scheduled flights are operated daily; the duration of any flight is less than 24 hours; town_from <> town_to;