I am trying to solve a slight variation of Problem G (Petya's Exams) in Contest #481. The original problem asks us to find out if Petya can complete ALL exams. This can be solved with a greedy approach as described in the tutorial. Now, what if we are asked to maximize the number of exams Petya can complete. To summarize, Given details of all exams and exam dates, how do we find out the maximum number of exams Petya can write.

Any pointers to solve this problem would be really helpful.