calculate business hours between two time stamp
<img width="488" alt="df" src="https://user-images.githubusercontent.com/55054825/71637854-1991c200-2c75-11ea-8090-b21ccb13ba93.PNG">

I have to calculate business hours between two time stamp. 
Challenge is Monday and Saturday have different business hours than rest of the weekdays.

Monday starts at 2:30 AM and ends at 11:59 PM. Saturday starts at 00:00 AM and ends at 6:30 AM.
Rest of the weekdays starts at 00:00 AM and ends at 11:59 PM. 
* All times are in IST. 

