Dear Sindhu,

JEE Advanced maximum marks are not defined :

Maximum Marks vary every year like below:

2017- 366

2016- 372

2015 - 504

2014 - 360

So, it is difficult to predict marks as exam pattern and marks change every year but you should score more than 50% marks to get good branch in Top IITs.

To get the idea about the cut off rank you can refer below link

https://engineering.careers360.com/colleges/indian-institute-of-technology-madras/cutoff

Good Luck!!