A trip from Chandigarh to Delhi takes six hours by bus. A typical time table of the bus service in

 both directions is given below:

Departure from Chandigarh	Route Number	Arrival at Delhi	Arrival at Chandigarh	Route Number	Departure from Delhi
6.00	a	12.00	11.30	1	5.30
7.30	b	13.30	15.00	2	9.00
11.30	c	17.30	21.00	3	15.00
19.00	d	01.00	00.30	4	18.30
00.30	e	6.30	06.00	5	00.00

The cost of providing this service by the transport company depends upon the time spent by the bus crew (driver and conductor) away from their places in addition to service time. There are five

crews. There is a constraint that every crew should be provided with more than 4 hours of rest before the return trip again and should not wait for more than 24 hours for the return trip. The

company has residential facilities for the crew at Chandigarh as well as at Delhi. Find the optimal service line connection.